Methods and systems for sequestering co 2 from ambient air

Abstract

Methods of sequestering CO2 from ambient air are provided. Methods of interest include directly contacting an aqueous capture liquid with the ambient air to produce a CO2 sequestering carbonate and CO2-depleted air. In some cases, methods of the invention do not include concentrating the CO2 from the ambient air prior to contacting it with the aqueous capture liquid. Systems for practicing the subject methods are also provided.

Description

[0001] METHODS AND SYSTEMS FOR SEQUESTERING CO2 FROM AMBIENT AIR

[0002] CROSS-REFERENCE TO RELATED APPLICATION

[0003] Pursuant to 35 U.S.C. §119(e), this application claims priority to the filing date of United States Provisional Patent Application Serial No. 63 / 664,950 filed June 27, 2024, the disclosure of which application is herein incorporated by reference.

[0004] INTRODUCTION

[0005] Carbon dioxide (CO2) is a naturally occurring chemical compound that is present in Earth's atmosphere as a gas. Sources of atmospheric CO2 are varied, and include humans and other living organisms that produce CO2in the process of respiration, as well as other naturally occurring sources, such as volcanoes, hot springs, and geysers.

[0006] Additional major sources of atmospheric CO2 include industrial plants. Many types of industrial plants (including cement plants, refineries, steel mills and power plants) combust various carbon-based fuels, such as fossil fuels and syngases. Fossil fuels that are employed include coal, natural gas, oil, petroleum coke and biofuels. Fuels are also derived from tar sands, oil shale, coal liquids, and coal gasification and biofuels that are made via syngas.

[0007] The environmental effects of CO2 are of significant interest. CO2 is commonly viewed as a greenhouse gas. The phrase "global warming" is used to refer to observed and continuing rise in the average temperature of Earth's atmosphere and oceans since the late 19th century. Because human activities since the industrial revolution have rapidly increased concentrations of atmospheric CO2, anthropogenic CO2 has been implicated in global warming and climate change, as well as increasing oceanic bicarbonate concentration. Ocean uptake of fossil fuel CO2 is now proceeding at about 1 million metric tons of CO2 per hour. Since the early 20th century, the Earth's mean surface temperature has increased by about 0.8 °C (1 .4 °F), with about two-thirds of the increase occurring since 1980.

[0008] The effects of global warming on the environment and for human life are numerous and varied. Some effects of recent climate change may already be occurring. Rising sea levels, glacier retreat, Arctic shrinkage, and altered patterns of agriculture are cited as direct consequences, but predictions for secondary and regional effects include extreme weather events, an expansion of tropical diseases, changes in the timing of seasonal patterns in ecosystems, and drastic economic impact.

[0009] Projected climate changes due to global warming have the potential to lead to future large-scale and possibly irreversible effects at continental and global scales. The likelihood, magnitude, and timing is uncertain and controversial, but some examples of projected climate changes include significant slowing of the ocean circulation that transports warm water to the North Atlantic, large reductions in the Greenland and Western Antarctic Ice Sheets, accelerated global warming due to carbon cycle feedbacks in the terrestrial biosphere, and releases of terrestrial carbon from permafrost regions and methane from hydrates in coastal sediments.

[0010] While a matter of scientific debate, it is believed that excess atmospheric CO2 is a significant contributing factor to global warming. Since the beginning of the Industrial Revolution, the concentration of COp has increased by about 100 parts-per-million (ppm) (i.e. , from 280 ppm to 380 ppm), and was recently observed to reach an average daily value of over 400 ppm. As such, there is great interest in the sequestration of CO2, particularly in a manner sufficient to at least ameliorate the ever-increasing amounts of anthropogenic CO2 that is present in the atmosphere.

[0011] Concerns over anthropogenic climate change and ocean acidification, have fueled an urgency to discover scalable, cost effective, methods of carbon capture and sequestration (CCS). Typically, methods of CCS separate pure CO2 from complex flue streams, compress the purified CO2, and finally inject it into underground saline reservoirs for geologic sequestration. These multiple steps are very energy and capital intensive. Carbonate mineralization is another method to sequester large amounts of CO2, in gigaton (Gt, i.e., 1 ,000,000,000 tons) volumes, sustainably.

[0012] Direct air capture (DAC) is one technique used to remove CO2 from ambient air. A DAC system is any system that captures CO2 directly from air and generates a product gas that includes CO2 at a higher concentration than that of the air that is input into the DAC system. DAC systems are systems that extract CO2 from the air using media that binds to CO2 but not to other atmospheric chemicals (such as nitrogen and oxygen). As air passes over the CO2 binding medium, CO2 "sticks" to the binding medium. In response to a stimulus, e.g., heat, humidity, etc., the bound CO2 may then be released from the binding medium resulting the production of a gaseous CO2 containing product. Known DAC systems include amine based systems, hydroxide-based systems, and CO2 sorbent / temperature swing based systems. The CO2 captured in this way is envisioned to be purified to liquid form for transporting it to other locations for geological sequestration in the subsurface or enhanced oil recovery, or refining carbon-based fuels for aviation or consumer products.

[0013] SUMMARY

[0014] The present inventors have realized that conventional techniques for sequestering CO2 such as DAC suffer from certain procedural inefficiencies. Particularly, the cost of DAC is prohibitively high, thereby preventing more widespread adoption of this technology. Due to the high parasitic energy demands of this approach, proponents plan to procure vast amounts of renewable energy from the grid to power the vary large subsidized envisioned DAC operations. As such, improved methods and systems for sequestering CO2 from ambient air are desirable. Embodiments of the invention satisfy this desire.

[0015] Aspects of the invention include methods of sequestering CO2 from ambient air. The subject methods include directly contacting an aqueous capture liquid with the ambient air to produce a CO2 sequestering carbonate and CC>2-depleted air to sequester the CO2 from the ambient air. Ambient air contacted with the aqueous capture liquid may, in some embodiments, have an amount of CO2 ranging from 300 ppm to 500 ppm. In addition, CO2-depleted air may have, in some embodiments, an amount of CO2 ranging from 100 ppm to 300 ppm. In some cases, directly contacting the aqueous capture liquid with the ambient air comprises drawing in the ambient air from a surrounding environment using a gas conveyor, and contacting the ambient air with the capture liquid. Gas conveyors may include, for example, an air pump or a turbine. In select embodiments, the gas conveyor is powered by a source of green energy, such as wind energy, hydroelectric energy, solar energy, geothermal energy or nuclear energy. The manner in which the aqueous capture liquid is contacted with the ambient air can include, for example, counter-current, co-current, or cross-current manners.

[0016] In some versions, methods additionally include gaseously cooling a source of waste heat. In select embodiments, methods include contacting the ambient air with the source of waste heat prior to the contact of the ambient air with the capture liquid. Alternatively, some embodiments of the subject methods include contacting the CO2- depleted air with the source of waste heat. In some instances, the method comprises gaseously cooling the source of waste heat via a heating, ventilation, and air conditioning (HVAC) system of the source of waste heat. The source of waste heat may include, e.g., a data center.

[0017] In some embodiments, methods also include (a) drawing in a C02-containing gas from a point source of gaseous CO2, and (b) contacting the aqueous capture liquid with the CC>2-containing gas. In some such cases, the C02-containing gas is a flue gas. In certain cases, methods include combusting a fuel (e.g., a natural gas) to drive the turbine, and thereby generating electricity and producing the CO2-containing gas. The point source of gaseous CO2 may include, for example, a power plant or an industrial plant. In select versions, methods include reducing the amount of ambient air being drawn in from the surrounding environment. In addition to steps (a)-(b), methods according to some embodiments of the invention may also include (c) determining that the point source of gaseous CO2is no longer emitting the CC>2-containing gas, and (d) resuming or continuing the contact of the aqueous capture liquid with the ambient air. In embodiments, methods include cyclically repeating steps (a)-(d). For example, steps (a)- (d) may be repeated according a cyclical availability of green energy (e.g., a day / night cycle). In some embodiments, the system may include repurposed equipment, such as a repurposed power plant which has been updated to perform DAC when not generating power.

[0018] In some cases, the aqueous capture liquid comprises an aqueous capture ammonia, and methods include producing a CO2 sequestering carbonate (e.g., CaCOs) by generating an aqueous ammonium salt. In some such cases, methods include regenerating aqueous capture ammonia from the aqueous ammonium salt. In certain versions, regenerating the aqueous capture ammonia from the aqueous ammonium salt comprises combining the aqueous ammonium salt with an alkalinity source, such as those produced by dissolving a geomass (e.g., demolished, recycled or returned concrete). In some embodiments, the method comprises contacting the aqueous capture ammonia with the ambient air under conditions sufficient to produce an aqueous carbonate, and then contacting the aqueous carbonate with cations from a cation source to produce the CO2 sequestering carbonate. In some instances, regenerating the aqueous capture ammonia from the aqueous ammonium salt comprises distillation. In alternative cases, the aqueous capture liquid comprises cations from a cation source, and the method comprises contacting the aqueous capture liquid with the ambient air under conditions sufficient to produce the CO2 sequestering carbonate. In some such cases, the method does not comprise purification of the regenerated aqueous ammonia. The cation source may include, for example, an alkaline earth metal cation (e.g., Ca2+, Mg2+, or a combination thereof). In some embodiments, methods include producing an aggregate from the CO2 sequestering carbonate.

[0019] Aspects of the invention also include systems. The subject systems include a CO2 sequestration unit configured to directly contact an aqueous capture liquid with the ambient air and produce CO2-depleted air. In some embodiments, the CO2sequestration unit is not configured to concentrate the CO2 from the ambient air prior to contacting it with the aqueous capture liquid, e.g., it is not configured to perform direct air capture (DAC). Systems according to some embodiments also include a gas conveyor (e.g., air pump, turbine) configured to draw the ambient air into the CO2 sequestration unit from a surrounding environment and contact the ambient air with the capture liquid. In some cases, the gas conveyor is powered by a source of green energy (e.g., wind energy, hydroelectric energy, solar energy, geothermal energy or nuclear energy). The CO2 sequestration unit may, in some embodiments, be configured to contact the aqueous capture liquid with the ambient air in a counter-current manner, a cross-current manner, or a co-current manner. Systems according to select versions of the invention also include a source of waste heat (e.g., data center) gaseously connected to the CO2 sequestration unit. In certain versions, the CO2 sequestration unit is gaseously connected to a heating, ventilation, and air conditioning (HVAC) system of the source of waste heat.

[0020] In some cases, the CO2 sequestration unit is gaseously connected to a point source of gaseous CO2 (e.g., power plant, industrial plant) configured to produce a CO2- containing gas. In certain versions, systems include a control unit operably connected to the point source of gaseous CO2. Control units of interest are configured to cause (a) the gas conveyor to draw in the C02-containing gas from the point source of gaseous CO2, (b) the CO2 sequestration unit to contact the CO2-containing gas with the aqueous capture liquid, (c) the point source of gaseous C02to cease providing the CO2- containing gas to the CO2 sequestration unit, and (d) the gas conveyor to resume or continue drawing in the ambient air. In some cases, the control unit is configured to activate and deactivate the point source of gaseous CO2. In select instances, the control unit is configured to cyclically repeat steps (a)-(d), for example, according to a cyclical availability of green energy (e.g., a day / night cycle).

[0021] In some embodiments, systems are configured to directly contact an aqueous capture liquid comprising an aqueous capture ammonia with the ambient air, produce a C02sequestering carbonate and an aqueous ammonium salt, and regenerate aqueous capture ammonia from the aqueous ammonium salt. In select instances, the system is configured to regenerate the aqueous capture ammonia from the aqueous ammonium salt by contacting the aqueous ammonium salt with an alkalinity source (e.g., produced by dissolving a geomass, such as a geomass comprising demolished, recycled or returned concrete). Systems according to select versions may include a reformer configured to regenerate the aqueous capture ammonia from the aqueous ammonium salt. In certain embodiments, the CO2sequestration unit is configured to produce an aqueous ammonium carbonate by contacting the ambient air with the aqueous capture ammonia. In some cases, systems include a reactor configured to combine cations from a cation source and the aqueous ammonium carbonate to produce the CO2sequestering carbonate and an aqueous ammonium salt. In some embodiments, the reformer is configured to regenerate the aqueous capture ammonia from the aqueous ammonium salt via distillation. In other cases, wherein the CO2 sequestration unit is configured to produce a CO2sequestering carbonate by contacting an aqueous ammonia capture liquid comprising cations from a cation source with the ambient air. In some such cases, the system is not configured to regenerate the aqueous capture ammonia via purification.

[0022] BRIEF DESCRIPTION OF THE FIGURES

[0023] The invention may be best understood from the following detailed description when read in conjunction with the accompanying drawings. Included in the drawings are the following figures:

[0024] FIG. 1 presents a flowchart for practicing methods of the invention according to certain embodiments.

[0025] FIGS. 2A-2B depict a system configured to directly contact an aqueous capture liquid with ambient air according to certain embodiments.

[0026] FIGS. 3A-3B depict a system configured to contact ambient air with a source of waste heat according to certain embodiments.

[0027] FIG. 4 provides a schematic representation of a system according to an embodiment of the invention.

[0028] FIG. 5 provides a schematic representation of a system according to an embodiment of the invention, where the system does not include a stripper or other ammonia purification module. FIG. 6A provides a schematic representation of a Natural Gas Combined Cycle (NGCC) power plant; and FIG. 6B provides a schematic representation of the same NGCC power plant repurposed for Direct Air Capture (DAC) in accordance with an embodiment of the invention.

[0029] DETAILED DESCRIPTION

[0030] Methods of sequestering CO2 from ambient air are provided. Methods of interest include directly contacting an aqueous capture liquid with the ambient air to produce a CO2 sequestering carbonate and CO2-depleted air. In some cases, methods of the invention do not include concentrating the CO2 from the ambient air prior to contacting it with the aqueous capture liquid. Systems for practicing the subject methods are also provided.

[0031] Before the present invention is described in greater detail, it is to be understood that this invention is not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

[0032] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

[0033] Certain ranges are presented herein with numerical values being preceded by the term "about." The term "about" is used herein to provide literal support for the exact number that it precedes, as well as a number that is near to or approximately the number that the term precedes. In determining whether a number is near to or approximately a specifically recited number, the near or approximating un-recited number may be a number which, in the context in which it is presented, provides the substantial equivalent of the specifically recited number. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, representative illustrative methods and materials are now described.

[0034] All publications and patents cited in this specification are herein incorporated by reference as if each individual publication or patent were specifically and individually indicated to be incorporated by reference and are incorporated herein by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed.

[0035] It is noted that, as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.

[0036] As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present invention. Any recited method can be carried out in the order of events recited or in any other order which is logically possible.

[0037] METHODS FOR SEQUESTERING CO2 FROM AMBIENT AIR

[0038] As discussed above, aspects of the invention include methods for sequestering CO2 from ambient air. When practiced, methods of the invention may improve the efficiency of CO2 sequestration relative to a conventional process such as DAC, e.g., by 1% or more, such as 5% or more, such as 10% or more, such as 15% or more, such as 20% or more, such as 25% or more, such as 30% or more, such as 35% or more, such as 40% or more, such as 45% or more, and including 50% or more. Furthermore, in some cases, practicing the invention reduces parasitic load by 1 % or more, such as 5% or more, such as 10% or more, such as 15% or more, such as 20% or more, such as 25% or more, such as 30% or more, such as 35% or more, such as 40% or more, such as 45% or more, and including 50% or more.

[0039] The subject methods include directly contacting an aqueous capture liquid with the ambient air. By “directly” contacting, it is meant that there is no intermediate process that the ambient air is subjected to prior to its contact with the capture liquid. In other words, the composition of the air is unaltered when contacted with the capture liquid. For example, the method does not include concentrating the CO2 from the ambient air prior to contacting it with the aqueous capture liquid. This is in contrast to DAC, which requires a concentration step. Put another way, the ambient air is not subjected to a hydroxide-based DAC process or a CO2 sorbent / temperature swing based DAC process. As such, the amount of CO2 in the ambient air used in the subject methods is the same as the surrounding environment. This amount may vary according to factors such as the number, type, and / or proximity of CC emitting entities surrounding the location at which the subject methods take place. In some cases, the ambient air has an amount of CO2 ranging from 200 ppm to 600 ppm, such as 225 ppm to 575 ppm, such as 250 ppm to 550 ppm, such as 275 ppm to 525 ppm, such as 300 ppm to 500 ppm, such as 325 ppm to 475 ppm, such as 350 ppm to 450 ppm, such as 375 ppm to 425 ppm, and including 380 ppm to 410 ppm.

[0040] Any organic or aqueous medium consistent with the above may be employed as the capture liquid and be contacted with the ambient air. In some cases, the capture liquid is an aqueous medium. In some embodiments, the capture liquid includes ammonia. In such embodiments, an aqueous capture ammonia is contacted with the gaseous source of CO2 under conditions sufficient to produce an aqueous ammonium carbonate.

[0041] In methods of the invention, the aqueous capture liquid is directly contacted with the ambient air in a manner sufficient to produce a CO2 sequestering carbonate and CO2-depleted air. By “CO2sequestering carbonate”, it is meant a carbonate material formed at least in part from CO2 captured by directly contacting the capture liquid with the ambient air. The CO2 sequestering carbonate may vary, and can include, e.g., calcium carbonate (CaCOs) and magnesium carbonate (MgCO3), or the like, as well as combinations thereof. In addition, “CC>2-depleted air” refers to ambient air from which an amount of CO2 has been removed, e.g., by capture or sequestration. In some embodiments, COs-depleted air still comprises an amount of CO2, i.e. , not all of the CO2 from the ambient air has been removed. For example, methods of the invention may be sufficient to CO2-depleted air that has 10% less CO2 (e.g., in ppm) than the ambient air or more, such as 15% less CO2 than the ambient air or more, such as 20% less CO2 than the ambient air or more, such as 25% less CO2 than the ambient air or more, such as 30% less CO2than the ambient air or more, such as 35% less CO2 than the ambient air or more, such as 40% less CO2 than the ambient air or more, such as 45% less CO2 than the ambient air or more, such as 50% less CO2 than the ambient air or more, such as 55% less CO2 than the ambient air or more, such as 60% less CO2 than the ambient air or more, and including 65% less CO2 than the ambient air or more. In some cases, the CC>2-depleted air comprises an amount of CO2 ranging from 1 ppm to 400 ppm, such as 25 ppm to 375 ppm, such as 50 ppm to 350 ppm, such as 75 ppm to 325 ppm, such as 100 ppm to 300 ppm, such as 125 ppm to 275 ppm, such as 150 ppm to 250 ppm, such as 175 ppm to 225 ppm, and including 190 ppm to 210 ppm.

[0042] The ambient air may be contacted with the aqueous capture liquid using any convenient protocol. For example, contact protocols of interest include, but are not limited to: direct contacting protocols, e.g., bubbling the gas through a volume of the aqueous medium, concurrent contacting protocols, i.e., contact between unidirectionally flowing gaseous and liquid phase streams, countercurrent protocols, i.e., contact between oppositely flowing gaseous and liquid phase streams, and the like. In some cases, the method comprises contacting the aqueous capture liquid with the ambient air in a co-current manner. Contact may be accomplished through use of infusers, bubblers, fluidic Venturi reactors, spargers, gas filters, sprays, trays, scrubbers, absorbers or packed column reactors, and the like, as may be convenient. In some instances, the contacting protocol may use a conventional absorber or an absorber froth column, such as those described in U.S. Patent Nos. 7,854,791 ; 6,872,240; and 6,616,733; and in United States Patent Application Publication US-2012-0237420-A1 ; the disclosures of which are herein incorporated by reference. The process may be a batch or continuous process. In some instances, a regenerative froth contactor (RFC) may be employed to contact the ambient air with the aqueous capture liquid, e.g., aqueous capture ammonia. In some such instances, the RFC may use a catalyst (such as described elsewhere), e.g., a catalyst that is immobilized on / to the internals of the RFC. Further details regarding a suitable RFC are found in U.S. Patent No. 9,545,598, the disclosure of which is herein incorporated by reference. In certain versions, directly contacting the aqueous capture liquid with the ambient air comprises drawing in the ambient air from a surrounding environment using a gas conveyor, and contacting the ambient air with the capture liquid. A “gas conveyor” may be any device suitable for causing the movement of a gas. In certain versions, the gas conveyor is an air pump. In other cases, the gas conveyor is a compressor. In still other cases, the gas conveyor is a turbine. In certain embodiments, e.g., as described in greater detail below, the gas conveyor is part of a repurposed power plant.

[0043] The gas conveyor may be powered by any convenience power source. In some instances, the gas conveyor is powered by a source of green energy. For the purposes of the present disclosure, a source of “green” energy may be any power source that results in minimal, including zero, CO2 output. In select embodiments, the source of green energy is selected from wind energy, hydroelectric energy, solar energy, geothermal energy, nuclear energy and the like, as well as combinations thereof. In certain versions, the source of green energy is wind energy. In other versions, the source of green energy is hydroelectric energy. In still other versions, the source of green energy is solar energy. In yet other versions, the source of green energy is geothermal energy. In still other embodiments, the source of green energy is nuclear energy.

[0044] Methods of the invention may additionally include (a) drawing in a COs-containing gas from a point source of gaseous CO2, and (b) contacting the aqueous capture liquid with the C02-containing gas. As discussed herein, the term “point source of gaseous CO2” is employed in its conventional sense to describe a single identifiable source of gaseous CO2 emissions (i.e., as opposed to CO2 present in the atmosphere, more generally). In certain embodiments, CO2 containing gasses are obtained from an industrial plant, e.g., where the CO2 containing gas is a waste from an industrial plant. Industrial plants from which the CO2 containing gas may be obtained, e.g., as a waste from the industrial plant, may vary. Industrial plants of interest include, but are not limited to, industrial product manufacturing plants, such as but not limited to chemical and mechanical processing plants, refineries, cement plants, smelters, steel plants, etc., as well as other industrial plants that produce CO2 as a byproduct of fuel combustion or other processing step (such as calcination by a cement plant or reformation in a hydrogen plant). Waste feeds of interest include gaseous streams that are produced by an industrial plant, for example as a secondary or incidental product, of a process carried out by the industrial plant. In other embodiments, CO2 containing gasses are obtained from a power plant.

[0045] Of interest in certain embodiments are waste streams produced by industrial plants or power plants that combust fossil fuels, e.g., coal, oil, natural gas, and their derivatives as well as man-made fuel products of naturally occurring organic fuel deposits, such as but not limited to tar sands, heavy oil, oil shale, etc., and their derivatives. In certain embodiments, power plants are pulverized coal power plants, supercritical coal power plants, mass burn coal power plants, fluidized bed coal power plants, gas or oil-fired boiler and steam turbine power plants, gas or oil-fired boiler simple cycle gas turbine power plants, and gas or oil-fired boiler combined cycle gas turbine power plants. Of interest in certain embodiments are waste streams produced by power plants that combust syngas, i.e. , gas that is produced by the gasification of organic matter, e.g., coal, biomass, etc., where in certain embodiments such plants are integrated gasification combined cycle (IGCC) plants. Of interest in certain embodiments are waste streams produced by Heat Recovery Steam Generator (HRSG) plants. Waste streams of interest also include waste streams produced by cement plants. Cement plants whose waste streams may be employed in methods of the invention include both wet process and dry process plants, which plants may employ shaft kilns or rotary kilns, and may include pre-calciners. Each of these types of industrial plants may burn a single fuel, or may burn two or more fuels sequentially or simultaneously. A waste stream of interest is industrial plant exhaust gas, e.g., a flue gas. By "flue gas" is meant a gas that is obtained from the products of combustion from burning a fossil or biomass fuel that are then directed to the smokestack, also known as the flue of an industrial plant or power plant.

[0046] The amount of CO2 in the CO2 containing gas, in some instances, may be 20,000 ppm or greater, e.g., 50,000 ppm or greater, such as 100,000 ppm or greater, including 150,000 ppm or greater, e.g., 500,000 ppm or greater, 750,000 ppm or greater, 900,000 ppm or greater, up to including 1 ,000,000 ppm (In pure CO2 exhaust the concentration is 1 ,000,000 ppm) In some instances may range from 10,000 to 500,000 ppm, such as 50,000 to 250,000 ppm, including 100,000 to 150,000 ppm. The temperature of the CO2 containing gas may also vary, ranging in some instances from 0 to 1800°C, such as 100 to 1200°C and including 600 to 700°C. In some instances the CO2 containing gasses are not pure CO2, in that they contain one or more additional gasses and / or trace elements. Additional gasses that may be present in the CO2containing gas include, but are not limited to water, nitrogen, mononitrogen oxides, e.g., NO, NO2, and NO3, oxygen, sulfur, monosulfur oxides, e.g., SO, SO2 and SO3), volatile organic compounds, e.g., benzo(a)pyrene C2OH12, benzo(g,h,l)perylene C22H12, dibenzo(a,h)anthracene C22H14, etc. Particulate components that may be present in the CO2 containing gas include, but are not limited to particles of solids or liquids suspended in the gas, e.g., heavy metals such as strontium, barium, mercury, thallium, etc.

[0047] The C02-containing gas may be drawn from the point source of gaseous CO2 via any convenient protocol. In some cases, the CO2-containing gas as it is emitted from the point source has a velocity sufficient such that it can be channeled to the capture liquid. In such cases, it is not required to apply a force to the gas to contact the C02-containing gas with the capture liquid. In some instances, the gas conveyor used to draw in ambient air from the surrounding environment may also be used in generating the C02-containing gas. For example, in instances where the gas conveyor is a turbine, methods may include combusting a fuel to drive the turbine, and thereby generating electricity and producing the CC>2-containing gas. In such instances, the turbine has a dual purpose. When it is desirable to contact ambient air with the capture liquid, power may be applied to the turbine so that it may draw ambient air. On the other hand, driving the turbine (e.g., via combustion) generates power and combusted fuel (i.e., the 002-containing gas). In some cases, while the 002-containing gas is drawn in from the point source of gaseous CO2 and contacted with the capture liquid, methods include at least reducing the amount of ambient air being drawn in from the surrounding environment. For example, in these cases, the activity of the gas conveyor may be adjusted such that the conveyance of ambient air to the capture liquid is reduced or ceased. In some cases where the 002-containing gas from the point source is being contacted with the capture liquid, methods include reducing the amount of ambient air being drawn in from the surrounding environment by 50% or more, such as 60% or more, such as 70% or more, such as 80% or more, such as 90% or more, and including by 100%.

[0048] Any suitable fuel may be employed. In certain cases, the subject fuel is any fuel that produces CO2when combusted. Fuels of interest may include, for example, one or more alkanes, alkenes, alkynes and aromatic compounds. In certain cases, fuels include methane (CH4), ethane (CaHe), propane (CsHs), butane (C4H10), pentane (C5H12), hexane (CeH ), heptane (C?HI6) or octane (C8HI8), higher molecular weight compounds, and combinations thereof. In certain cases, the fuel oxidized in the present disclosure is a natural gas. The “natural gasses” discussed herein are referred to in their conventional sense to describe naturally occurring hydrocarbon gas mixtures. In some embodiments, the subject natural gasses may additionally include one or more of the following: alkanes, CO2, N2, H2S, and Hg. In some cases, the natural gasses employed herein have been subjected to natural-gas processing (i.e., the removal of impurities). In such cases, the natural gasses oxidized in the subject methods may have been processed such that one or more of the following have been removed: H2S, Hg, H2O, CO2, high molecular weight compounds, and solids. Any suitable natural gas processing protocol may be employed. Natural gas processing is described in, e.g., U.S. Pat. No. 10,753,678; the disclosure of which is incorporated by reference herein in its entirety.

[0049] Like the ambient air, the CO2-containing gas may be contacted with the capture liquid via any convenient protocol. In certain cases, the CO2-containing gas is contacted with the capture liquid using one or more of the protocols described above. In select instances, the CO2-containing gas is contacted with the capture liquid using the same protocol used for the ambient air. In some embodiments, methods include contacting the aqueous capture liquid with the C02-containing gas in a counter-current manner. In other embodiments, methods include contacting the aqueous capture liquid with the CO2- containing gas in a co-current manner. In still other embodiments, methods include contacting the aqueous capture liquid with the C02-containing gas in a cross-current manner.

[0050] In some embodiments, methods additionally include (c) determining that the point source of gaseous CO2is no longer emitting the CO2-containing gas, and (d) resuming or continuing the contact of the aqueous capture liquid with the ambient air. The determination can be made, e.g., when the point source has reduced and / or ceased operation for a period of time. For example, where the point source is comprised of an industrial plant, the industrial plant may operate on a certain schedule, e.g., where the plant is operational during the day but not at night. Therefore, in some cases, the determination is made when the point source (e.g., power plant, industrial plant) has ceased operations for the day. Where methods include at least reducing the amount of ambient air being drawn in from the surrounding environment as part of steps (a)-(b), step (d) can include resuming / increasing the contact of the aqueous capture liquid with the ambient air. Otherwise, the contact of the aqueous capture liquid with the ambient air is continued.

[0051] Methods according to some embodiments of the invention include cyclically repeating steps (a)-(d). By “cyclically” repeating the steps, it is meant that step (a) is performed again after step (d) such that the steps repeat as a cycle. These steps may be repeated any number of times. For example, in some cases, steps (a)-(d) are repeated 2 or more times, 10 or more times, 50 or more times, 100 or more times, 500 or more times, 1000 or more times, 5000 or more times, 10000 or more times, 50000 or more times and including 1000000 or more times. In some cases, methods include cyclically repeating steps (a)-(d) an indefinite number of times. In select instances, methods include repeating steps (a)-(d) according to a cyclical availability of green energy. In other words, the performance of the steps are at least partially determined by whether the green energy is available at a given time. In some embodiments, the contacting of the aqueous capture liquid with the COz-containing gas from the point source (i.e. , steps (a)-(b)) occurs when there is a low availability of green energy, while the contacting of the ambient air with the capture liquid (i.e., steps (c)-(d)) occurs when there is a comparatively higher availability of green energy. In an example where the source of green energy is wind, the contacting of the aqueous capture liquid with the COz-containing gas from the point source (i.e., steps (a)-(b)) occurs when winds are low, while the contacting of the ambient air with the capture liquid (i.e., steps (c)-(d)) occurs when there is a comparatively higher availability of wind. In some embodiments, the method comprises repeating steps (a)-(d) according to a day / night cycle. In an example where the source of green energy is solar, the contacting of the aqueous capture liquid with the COz-containing gas from the point source (i.e., steps (a)-(b)) occurs during the night time when the availability of solar energy is low, while the contacting of the ambient air with the capture liquid (i.e., steps (c)-(d)) occurs during the day time when the availability of solar energy is high.

[0052] FIG. 1 presents a flowchart for practicing methods of the invention according to certain embodiments. Step 101 includes directly contacting an aqueous capture liquid with the ambient air to produce a COz sequestering carbonate and COz-depleted air to sequester the COz from the ambient air. In step 102 (i.e., step (a)), a COz-containing gas is drawn in from a point source of gaseous COz. Step 103 (i.e., step (b)) includes contacting the aqueous capture liquid with the COz-containing gas. Step 104 (i.e., step (c)) includes determining that the point source of gaseous COz is no longer emitting the COz-containing gas. After step 104, the contact of the aqueous capture liquid with the ambient air is resumed (i.e., step (d)), and the method returns to step 101 .

[0053] In some cases, methods of the invention also include gaseously cooling a source of waste heat. In such cases, the process of drawing in ambient air to sequester COz therefrom may be coupled with a process of cooling an object or area in need of such cooling. The ambient air may be used to cool the source of waste heat before or after said air is contacted with the capture liquid. In some embodiments, methods include contacting the ambient air with the source of waste heat prior to the contact of the ambient air with the capture liquid. In other embodiments, methods include contacting the CO2-depleted air with the source of waste heat. Any convenient source of waste heat may be cooled via the subject methods. Sources of waste heat include, but are not limited to machinery, computers, homes, and the like. In some cases, the source of waste heat is a data center. In select instances, the method comprises gaseously cooling the source of waste heat via a heating, ventilation, and air conditioning (HVAC) system of the source of waste heat. In some such instances, the gas conveyor moves air through the HVAC system thereby cooling the components associated with the HVAC system.

[0054] In some cases, an aqueous capture liquid is contacted with the ambient air and / or gaseous source of CO2under conditions sufficient to produce a CO2sequestering material. The CO2sequestering material may be produced from the gaseous source of CO2and capture liquid by using a multistep or single step protocol, as desired. For example, in some embodiments, combination of the CO2capture liquid and ambient air and / or gaseous source of CO2results in production of an aqueous carbonate, which aqueous carbonate is then subsequently contacted with a divalent cation source, e.g., a Ca2+and / or Mg2+source, to produce the CO2sequestering material. In yet other embodiments, a one-step CO2gas absorption carbonate precipitation protocol is employed.

[0055] Where the aqueous capture liquid is an aqueous capture ammonia, the concentration of ammonia in the aqueous capture ammonia may vary, where in some instances the aqueous capture ammonia includes ammonia (NH3) at a concentration ranging from 0.1 to 20.0 moles per liter (M), and in some instances 0.1 to 5.0 M, such as 0.1 to 4.0 M, e.g., 4.0 M, while in other instances from 2 to 20 M, such as 4 to 20 M. The aqueous capture ammonia may include any convenient water. Waters of interest from which the aqueous capture ammonia may be produced include, but are not limited to, freshwaters, seawaters, brine waters, produced waters and waste waters. In some instances the water of interest may be recycled water from a wastewater treatment plant, wherein the recycled water already includes NH3at a concentration ranging from 10 to 500 ppm, and in some instances 10 to 100 ppm, such as 10 to 90 ppm, while in other instances from 100 to 500 ppm, such as from 150 to 500 ppm NH3. The pH of the aqueous capture ammonia may vary, ranging in some instances from 10.0 to 13.5, such as 10.0 to 13.0, including 10.5 to 12.5. Further details regarding aqueous capture ammonias of interest are provided in PCT published application No. WO / 2017 / 165849; the disclosure of which is herein incorporated by reference.

[0056] The temperature of the liquid medium that is contacted with the ambient air may vary. In some instances, the temperature ranges from -1.4 to 100°C, such as 20 to 80°C and including 40 to 70°C. In some instances, the temperature may range from -1 .4 to 50 °C or higher, such as from -1.1 to 45 °C or higher. In some instances, cool water temperatures are employed, where such temperatures may range from -1 .4 to 4°C, such as -1 .1 to 0 °C. While an initial aqueous media may be cooled to obtain the desired temperature, in some instances a natural source of the aqueous media having the desired optimal temperature may be employed. For example, where the aqueous medium is ocean or seawater, the ocean or sea water may be obtained from a location where the water has the desired temperature. In some instances, obtaining such water may include obtaining the water from a depth below the surface of the water (e.g., the surface of the ocean), where the depth may range in some instances from 10 to 2000 meters, such as 20 to 200 m.

[0057] In some instances, warmer temperatures are employed. For example, the temperature of the liquid medium in some instances may be 25°C or higher, such as 30°C or higher, and may in some embodiments range from 25 to 50°C, such as 30 to 40°C. While a given liquid medium may be warmed in such instances to arrive at these temperatures, in some instances the liquid medium may be obtained from a naturally occurring source which is at the desired warm temperature, or obtained from a manmade source that provides the desired temperature, e.g., from the output of an industrial, e.g., power, plant cooling system, etc.

[0058] In some cases, contact is carried out in manner sufficient to produce an aqueous ammonium carbonate. The aqueous ammonium carbonate may vary, where in some instances the aqueous ammonium carbonate comprises at least one of ammonium carbonate and ammonium bicarbonate and in some instances comprises both ammonium carbonate and ammonium bicarbonate. The aqueous ammonium bicarbonate may be viewed as a dissolved inorganic carbon (DIC) containing liquid. As such, in charging the aqueous capture ammonia with CO2, a DAC generated CO2 containing gas may be contacted with CO2 capture liquid under conditions sufficient to produce DIG in the CO2 capture liquid, i.e., to produce a DIC containing liquid. The DIC is the sum of the concentrations of inorganic carbon species in a solution, represented by the equation: DIC = [CO2*] + [HCO3 ] + [CO32], where [CO2*] is the sum of carbon dioxide ([CO2]) and carbonic acid ([H2CO3]) concentrations, [HCO3 ] is the bicarbonate concentration (which includes ammonium bicarbonate) and [CO32] is the carbonate concentration(which includes ammonium carbonate) in the solution. The DIC of the aqueous media may vary, and in some instances may be 5,000 ppm carbon or greater, such as 10,000 ppm carbon or greater, including 15,000 ppm carbon or greater. In some instances, the DIC of the aqueous media may range from 5,000 to 50,000 ppm carbon, such as 7,500 to 15,000 ppm carbon, including 8,000 to 12,000 ppm carbon. The amount of CO2 dissolved in the liquid may vary, and in some instances ranges from 0.05 to 40 mM, such as 1 to 35 mM, including 25 to 30 mM. The pH of the resultant DIC containing liquid may vary, ranging in some instances from 4 to 12, such as 6 to 11 and including 7 to 10, e.g., 8 to 8.5.

[0059] Where desired, the ambient air and / or CO2 containing gas is contacted with the capture liquid in the presence of a catalyst (i.e., an absorption catalyst, either hetero- or homogeneous in nature) that mediates the conversion of CO2 to bicarbonate. Of interest as absorption catalysts are catalysts that, at pH levels ranging from 8 to 10, increase the rate of production of bicarbonate ions from dissolved CO2. The magnitude of the rate increase (e.g., as compared to control in which the catalyst is not present) may vary, and in some instances is 2-fold or greater, such as 5-fold or greater, e.g., 10-fold or greater, as compared to a suitable control. Further details regarding examples of suitable catalysts for such embodiments are found in U.S. Patent No. 9,707,513, the disclosure of which is herein incorporated by reference.

[0060] In some embodiments, the resultant aqueous ammonium carbonate is a two phase liquid which includes droplets of a liquid condensed phase (LCP) in a bulk liquid, e.g., bulk solution. By “liquid condensed phase” or “LCP” is meant a phase of a liquid solution which includes bicarbonate ions wherein the concentration of bicarbonate ions is higher in the LCP phase than in the surrounding, bulk liquid. LCP droplets are characterized by the presence of a meta-stable bicarbonate-rich liquid precursor phase in which bicarbonate ions associate into condensed concentrations exceeding that of the bulk solution and are present in a non-crystalline solution state. The LCP contains all of the components found in the bulk solution that is outside of the interface. However, the concentration of the bicarbonate ions is higher than in the bulk solution. In those situations where LCP droplets are present, the LCP and bulk solution may each contain ion-pairs and pre-nucleation clusters (PNCs). When present, the ions remain in their respective phases for long periods of time, as compared to ion-pairs and PNCs in solution. Further details regarding LCP containing liquids are provided in U.S. Patent No. 9,707,513, the disclosure of which is herein incorporated by reference.

[0061] As reviewed above, both multistep and single step protocols may be employed to produce the CO2 sequestering carbonate material from the CO2 containing gas the aqueous capture ammonia. For example, in some embodiments the product aqueous ammonium carbonate is forwarded to a CO2 sequestering carbonate production module, where divalent cations, e.g., Ca2+and / or Mg2+, are combined with the aqueous ammonium carbonate to produce the CO2 sequestering carbonate. In yet other instances, aqueous capture ammonia includes a source of divalent cations, e.g., Ca2+and / or Mg2+, such that aqueous ammonium carbonate combines withe divalent cations as it is produced to result in production of a CO2 sequestering carbonate.

[0062] Accordingly, in some embodiments, following production of an aqueous carbonate, such as an aqueous ammonium carbonate, e.g., as described above, the aqueous carbonate is subsequently combined with a cation source under conditions sufficient to produce a solid CO2 sequestering carbonate. Cations of different valances can form solid carbonate compositions (e.g., in the form of carbonate minerals). In some instances, monovalent cations, such as sodium and potassium cations, may be employed. In other instances, divalent cations, such as alkaline earth metal cations, e.g., calcium (Ca2+) and magnesium (Mg2+) cations, may be employed. When cations are added to the aqueous carbonate, precipitation of carbonate solids, such as amorphous calcium carbonate (CaCOs) when the divalent cations include Ca2+, may be produced with a stoichiometric ratio of one carbonate-species ion per cation.

[0063] Any convenient cation source may be employed in such instances. Cation sources of interest include, but are not limited to, the brine from water processing facilities such as sea water desalination plants, brackish water desalination plants, groundwater recovery facilities, wastewater facilities, blowdown water from facilities with cooling towers, and the like, which produce a concentrated stream of solution high in cation contents. Also of interest as cation sources are naturally occurring sources, such as but not limited to native seawater and geological brines, which may have varying cation concentrations and may also provide a ready source of cations to trigger the production of carbonate solids from the aqueous ammonium carbonate. In some instances, the cation source may be a waste product of another step of the process, e.g., a calcium salt (such as CaCI2) produced during regeneration of ammonia from the aqueous ammonium salt.

[0064] In yet other embodiments, the aqueous capture ammonia includes cations, e.g., as described above. The cations may be provided in the aqueous capture ammonia using any convenient protocol. In some instances, the cations present in the aqueous capture ammonia are derived from a geomass used in regeneration of the aqueous capture ammonia from an aqueous ammonium salt. In addition and / or alternatively, the cations may be provided by combining an aqueous capture ammonia with a cation source, e.g., as described above.

[0065] The product CO2 sequestering carbonate compositions produced by embodiments of methods of the invention may vary greatly. The precipitated product may include one or more different carbonate compounds, such as two or more different carbonate compounds, e.g., three or more different carbonate compounds, five or more different carbonate compounds, etc., including non-distinct, amorphous carbonate compounds. Carbonate compounds of precipitated products of the invention may be compounds having a molecular formulation Xm(CC>3)n where X is any element or combination of elements that can chemically bond with a carbonate group or its multiple, wherein X is in certain embodiments an alkaline earth metal and not an alkali metal; wherein m and n are stoichiometric positive integers. These carbonate compounds may have a molecular formula of Xm(CO3)n H2O, where there are one or more structural waters in the molecular formula. The amount of carbonate in the product, as determined by coulometry using the protocol described as coulometric titration or by loss on ignition (LOI) using the standard test methods for LOI of solid combustion residues per ASTM D7348, may be 40% or higher, such as 70% or higher, including 80% or higher.

[0066] The carbonate compounds of the precipitated products may include a number of different cations, such as but not limited to ionic species of: calcium, magnesium, sodium, potassium, sulfur, boron, silicon, strontium, and combinations thereof. Of interest are carbonate compounds of divalent metal cations, such as calcium and magnesium carbonate compounds. Specific carbonate compounds of interest include, but are not limited to: calcium carbonate minerals, magnesium carbonate minerals and calcium magnesium carbonate minerals. Calcium carbonate minerals of interest include, but are not limited to: calcite (CaCOs), aragonite (CaCOs), vaterite (CaCOs), ikaite (CaCO3-6H2O), and amorphous calcium carbonate (CaCOs). Magnesium carbonate minerals of interest include, but are not limited to magnesite (MgCOs), barringtonite (MgCC>3-2H2O), nesquehonite (MgCO3-3H2O), lanfordite (MgCO3-5H2O), hydromagnesite, and amorphous magnesium calcium carbonate (MgCOs). Calcium magnesium carbonate minerals of interest include, but are not limited to dolomite (CaMg)(CO3)2), huntite (Mg3Ca(CO3)4) and sergeevite (Ca2Mgn(CO3)i3 H2O). The carbonate compounds of the product may include one or more waters of hydration, or may be anhydrous. In some instances, the amount by weight of magnesium carbonate compounds in the precipitate exceeds the amount by weight of calcium carbonate compounds in the precipitate. For example, the amount by weight of magnesium carbonate compounds in the precipitate may exceed the amount by weight calcium carbonate compounds in the precipitate by 5% or more, such as 10% or more, 15% or more, 20% or more, 25% or more, 30% or more. In some instances, the weight ratio of magnesium carbonate compounds to calcium carbonate compounds in the precipitate ranges from 1 .5 - 5 to 1 , such as 2-4 to 1 including 2-3 to 1 . In some instances, the precipitated product may include hydroxides, such as divalent metal ion hydroxides, e.g., calcium and / or magnesium hydroxides.

[0067] Further details regarding carbonate production and methods of using the carbonated produced thereby are provided in: U.S. Patent Nos. 9,707,513; 9,714,406; 9,993,79910,71 1 ,236; 10,203,434; 10,197,747; the disclosures of which are herein incorporated by reference.

[0068] In some instances, carbonate production occurs in a continuous fashion, e.g., as described in U.S. Patent No. 9,993,799, the disclosure of which is herein incorporated by reference. In some such instances, carbonate production may occur in the presence of a seed structure. By seed structure is meant a solid structure or material that is present flowing liquid, e.g., in the material production zone, prior to divalent cation introduction into the liquid. By "in association with" is meant that the material is produced on at least one of a surface of or in a depression, e.g., a pore, crevice, etc., of the seed structure. In such instances, a composite structure of the carbonate material and the seed structure is produced. In some instances, the product carbonate material coats a portion, if not all of, the surface of a seed structure, e.g., a carbonate coated seed structure. In some instances, the product carbonate materials fills in a depression of the seed structure, e.g., a pore, crevice, fissure, etc. Seed structures may vary widely as desired. The term "seed structure" is used to describe any object upon and / or in which the product carbonate material forms. Seed structures may range from singular objects or particulate compositions, as desired. Where the seed structure is a singular object, it may have a variety of different shapes, which may be regular or irregular, and a variety of different dimensions. Shapes of interest include, but are not limited to, rods, meshes, blocks, etc. Also of interest are particulate compositions, e.g., granular compositions, made up of a plurality of particles. Where the seed structure is a particulate composition, the dimensions of particles may vary, ranging in some instances from 0.01 to 1 ,000,000 pm, such as 0.1 to 100,000 pm.

[0069] The seed structure may be made up of any convenient material or materials. Materials of interest include both carbonate materials, such as described above, as well as non-carbonate materials. The seed structures may be naturally occurring, e.g., naturally occurring sands, shell fragments from oyster shells or other carbonate skeletal allochems, gravels, etc., or man-made, such as pulverized rocks, ground blast furnace slag, fly ash, cement kiln dust, red mud, returned concrete, recycled concrete, demolished concrete and the like. For example, the seed structure may be a granular composition, such as sand, which is coated with the carbonate material during the process, e.g., a white carbonate material or colored carbonate material, e.g., as described above.

[0070] In some instances, seed structure may be coarse aggregates, such as friable Pleistocene coral rock, e.g., as may be obtained from tropical areas (e.g., Florida) that are too weak to serve as aggregate for concrete. In this case the friable coral rock can be used as a seed, and the solid CO2 sequestering carbonate mineral may be deposited in the internal pores, making the coarse aggregate suitable for use in concrete, allowing it to pass the Los Angeles abrasion test per AASHTO 96 and ASTMs C131 or C535. In some instances, where a lightweight aggregate is desired, the outer surface will only be penetrated by the solution of deposition, leaving the inner core relatively ‘hollow’ making a light weight aggregate for use in light weight concrete.

[0071] Production of Materials from the CO2 Sequestering Carbonate Product

[0072] The product carbonate material may be further used, manipulated and / or combined with other compositions to produce a variety of end-use materials. In certain embodiments, the product carbonate composition is refined (i.e., processed) in some manner. Refinement may include a variety of different protocols. In certain embodiments, the product is subjected to mechanical refinement, e.g., grinding, in order to obtain a product with desired physical properties, e.g., particle size, etc. In certain embodiments, the product is combined with a hydraulic cement, e.g., as a sand, a gravel, as an aggregate, etc., e.g., to produce final product, e.g., concrete or mortar.

[0073] Also of interest are formed building materials. The formed building materials of the invention may vary greatly. By "formed" is meant shaped, e.g., molded, cast, cut or otherwise produced, into a man-made structure defined physical shape, i.e. , configuration. Formed building materials are distinct from amorphous building materials, e.g., particulate (such as powder) compositions that do not have a defined and stable shape, but instead conform to the container in which they are held, e.g., a bag or other container. Illustrative formed building materials include, but are not limited to: bricks; boards; conduits; beams; basins; columns; drywalls etc. Further examples and details regarding formed building materials include those described in U.S. Patent No. 7,771 ,684; the disclosure of which is herein incorporated by reference.

[0074] Also of interest are non-cementitious manufactured items that include the product of the invention as a component. Non-cementitious manufactured items of the invention may vary greatly. By non-cementitious is meant that the compositions are not hydraulic cements. As such, the compositions are not dried compositions that, when combined with a setting fluid, such as water, set to produce a stable product. Illustrative compositions include, but are not limited to: paper products; polymeric products; lubricants; asphalt products; paints; personal care products, such as cosmetics, toothpastes, deodorants, soaps and shampoos; human ingestible products, including both liquids and solids; agricultural products, such as soil amendment products and animal feeds; etc. Further examples and details non-cementitious manufactured items include those described in United States Patent No. 7,829,053; the disclosure of which is herein incorporated by reference.

[0075] Ammonia Regeneration

[0076] As summarized above, production of CO2 sequestering carbonate from the aqueous ammonia capture liquid and the gaseous source of CO2 yields an aqueous ammonium salt. The produced aqueous ammonium salt may vary with respect to the nature of the anion of the ammonium salt, where specific ammonium salts that may be present in the aqueous ammonium salt include, but are not limited to, ammonium chloride, ammonium acetate, ammonium sulfate, ammonium nitrate, etc. As reviewed above, aspects of the invention further include regenerating an aqueous capture ammonia, e.g., as described above, from the aqueous ammonium salt. By regenerating an aqueous capture ammonia is meant processing the aqueous ammonium salt in a manner sufficient to generate an amount of ammonia from the aqueous ammonium salt. The percentage of input ammonium salt that is converted to ammonia during this regeneration step may vary, ranging in some instances from 20 to 80%, such as 35 to 55%.

[0077] Ammonia may be regenerated from an aqueous ammonium salt in this regeneration step using any convenient regeneration protocol. In some instances, a distillation protocol is employed. While any convenient distillation protocol may be employed, in some embodiments the employed distillation protocol includes heating the aqueous ammonium salt in the presence of an alkalinity source, e.g., geomass, to produce a gaseous ammonia / water product, which may then be condensed to produce a liquid aqueous capture ammonia. In some instances, the protocol happens continuously in a stepwise process wherein heating the aqueous ammonium salt in the present of an alkalinity source happens before the distillation and condensation of liquid aqueous capture ammonia.

[0078] The alkalinity source may vary, so long as it is sufficient to convert ammonium in the aqueous ammonium salt to ammonia. Any convenient alkalinity source may be employed. Alkalinity sources that may be employed in this regeneration step include chemical agents. Chemical agents that may be employed as alkalinity sources include, but are not limited to, hydroxides, organic bases, super bases, oxides, and carbonates. Hydroxides include chemical species that provide hydroxide anions in solution, including, for example, sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), or magnesium hydroxide (Mg(OH)2). Organic bases are carbon-containing molecules that are generally nitrogenous bases including primary amines such as methyl amine, secondary amines such as diisopropylamine, tertiary such as diisopropylethylamine, aromatic amines such as aniline, heteroaromatics such as pyridine, imidazole, and benzimidazole, and various forms thereof. Super bases suitable for use as proton-removing agents include sodium ethoxide, sodium amide (NaNH2), sodium hydride (NaH), butyl lithium, lithium diisopropylamide, lithium diethylamide, and lithium bis(trimethylsilyl)am ide. Oxides including, for example, calcium oxide (CaO), magnesium oxide (MgO), strontium oxide (SrO), beryllium oxide (BeO), and barium oxide (BaO) are also suitable proton-removing agents that may be used. Also of interest as alkalinity sources are silica sources. The source of silica may be pure silica or a composition that includes silica in combination with other compounds, e.g., minerals, so long as the source of silica is sufficient to impart desired alkalinity. In some instances, the source of silica is a naturally occurring source of silica. Naturally occurring sources of silica include silica containing rocks, which may be in the form of sands or larger rocks. Where the source is larger rocks, in some instances the rocks have been broken down to reduce their size and increase their surface area. Of interest are silica sources made up of components having a longest dimension ranging from 0.01 mm to 1 meter, such as 0.1 mm to 500 cm, including 1 mm to 100 cm, e.g., 1 mm to 50 cm. The silica sources may be surface treated, where desired, to increase the surface area of the sources. A variety of different naturally occurring silica sources may be employed. Naturally occurring silica sources of interest include, but are not limited to, igneous rocks, which rocks include: ultramafic rocks, such as Komatiite, Picrite basalt, Kimberlite, Lamproite, Peridotite; mafic rocks, such as Basalt, Diabase (Dolerite) and Gabbro; intermediate rocks, such as Andesite and Diorite; intermediate felsic rocks, such as Dacite and Granodiorite; and Felsic rocks, such as Rhyolite, Aplite — Pegmatite and Granite. Also of interest are man-made sources of silica. Man-made sources of silica include, but are not limited to, waste streams such as: mining wastes; fossil fuel burning ash; slag, e.g. iron and steel slags, phosphorous slag; cement kiln waste; oil refinery / petrochemical refinery waste, e.g. oil field and methane seam brines; coal seam wastes, e.g. gas production brines and coal seam brine; paper processing waste; water softening, e.g. ion exchange waste brine; silicon processing wastes; agricultural waste; metal finishing waste; high pH textile waste; and caustic sludge. Mining wastes include any wastes from the extraction of metal or another precious or useful mineral from the earth. Wastes of interest include wastes from mining to be used to raise pH, including: red mud from the Bayer aluminum extraction process; the waste from magnesium extraction for sea water, e.g. at Moss Landing, Calif.; and the wastes from other mining processes involving leaching. Ash from processes burning fossil fuels, such as coal fired power plants, create ash that is often rich in silica. In some embodiments, ashes resulting from burning fossil fuels, e.g. coal fired power plants, are provided as silica sources, including fly ash, e.g., ash that exits out the smoke stack, and bottom ash. Additional details regarding silica sources and their use are described in U.S. patent No. 9,714,406; the disclosure of which is herein incorporated by reference. In embodiments of the invention, ash is employed as an alkalinity source. Of interest in certain embodiments is use of a coal ash as the ash. The coal ash as employed in this invention refers to the residue produced in power plant boilers or coal burning furnaces, for example, chain grate boilers, cyclone boilers and fluidized bed boilers, from burning pulverized anthracite, lignite, bituminous or sub-bituminous coal. Such coal ash includes fly ash which is the finely divided coal ash carried from the furnace by exhaust or flue gases; and bottom ash which collects at the base of the furnace as agglomerates.

[0079] Fly ashes are generally highly heterogeneous, and include of a mixture of glassy particles with various identifiable crystalline phases such as quartz, mullite, and various iron oxides. Fly ashes of interest include Type F and Type C fly ash. The Type F and Type C fly ashes referred to above are defined by CSA Standard A23.5 and ASTM C618 as mentioned above. The chief difference between these classes is the amount of calcium, silica, alumina, and iron content in the ash. The chemical properties of the fly ash are largely influenced by the chemical content of the coal burned (i.e., anthracite, bituminous, and lignite). Fly ashes of interest include substantial amounts of silica (silicon dioxide, SiOz) (both amorphous and crystalline) and lime (calcium oxide, CaO, magnesium oxide, MgO).

[0080] The burning of harder, older anthracite and bituminous coal typically produces Class F fly ash. Class F fly ash is pozzolanic in nature, and contains less than 10% lime (CaO). Fly ash produced from the burning of younger lignite or subbituminous coal, in addition to having pozzolanic properties, also has some self-cementing properties. In the presence of water, Class C fly ash will harden and gain strength over time. Class C fly ash generally contains more than 20% lime (CaO). Alkali and sulfate (SO? ) contents are generally higher in Class C fly ashes. In some embodiments it is of interest to use Class C fly ash to regenerate ammonia from an aqueous ammonium salt, e.g., as mentioned above, with the intention of extracting quantities of constituents present in Class C fly ash so as to generate a fly ash closer in characteristics to Class F fly ash, e.g., extracting 95% of the CaO in Class C fly ash that has 20% CaO, thus resulting in a remediated fly ash material that has 1% CaO.

[0081] Fly ash material solidifies while suspended in exhaust gases and is collected using various approaches, e.g., by electrostatic precipitators or filter bags. Since the particles solidify while suspended in the exhaust gases, fly ash particles are generally spherical in shape and range in size from 0.5 pm to 100 pm. Fly ashes of interest include those in which at least about 80%, by weight comprises particles of less than 45 microns. Also of interest in certain embodiments of the invention is the use of highly alkaline fluidized bed combustor (FBC) fly ash.

[0082] Also of interest in embodiments of the invention is the use of bottom ash. Bottom ash is formed as agglomerates in coal combustion boilers from the combustion of coal. Such combustion boilers may be wet bottom boilers or dry bottom boilers. When produced in a wet or dry bottom boiler, the bottom ash is quenched in water. The quenching results in agglomerates having a size in which 90% fall within the particle size range of 0.1 mm to 20 mm, where the bottom ash agglomerates have a wide distribution of agglomerate size within this range. The main chemical components of a bottom ash are silica and alumina with lesser amounts of oxides of Fe, Ca, Mg, Mn, Na and K, as well as sulphur and carbon. Also of interest in certain embodiments is the use of volcanic ash as the ash. Volcanic ash is made up of small tephra, i.e. , bits of pulverized rock and glass created by volcanic eruptions, less than 2 millimeters in diameter.

[0083] In one embodiment of the invention, cement kiln dust (CKD) is employed as an alkalinity source. The nature of the fuel from which the ash and / or CKD were produced, and the means of combustion of said fuel, will influence the chemical composition of the resultant ash and / or CKD. Thus ash and / or CKD may be used as a portion of the means for adjusting pH, or the sole means, and a variety of other components may be utilized with specific ashes and / or CKDs, based on chemical composition of the ash and / or CKD.

[0084] In certain embodiments of the invention, slag is employed as an alkalinity source. The slag may be used as a as the sole pH modifier or in conjunction with one or more additional pH modifiers, e.g., ashes, etc. Slag is generated from the processing of metals, and may contain calcium and magnesium oxides as well as iron, silicon and aluminum compounds. In certain embodiments, the use of slag as a pH modifying material provides additional benefits via the introduction of reactive silicon and alumina to the precipitated product. Slags of interest include, but are not limited to, blast furnace slag from iron smelting, slag from electric-arc or blast furnace processing of iron and / or steel, copper slag, nickel slag and phosphorus slag.

[0085] As indicated above, ash (or slag in certain embodiments) is employed in certain embodiments as the sole way to modify the pH of the water to the desired level. In yet other embodiments, one or more additional pH modifying protocols is employed in conjunction with the use of ash. Also of interest in certain embodiments is the use of other waste materials, e.g., crushed or demolished or recycled or returned concretes or mortars, as an alkalinity source. When employed, the concrete dissolves releasing sand and aggregate which, where desired, may be recycled to the carbonate production portion of the process. Use of demolished and / or recycled concretes or mortars is further described below.

[0086] Of interest in certain embodiments are mineral alkalinity sources. The mineral alkalinity source that is contacted with the aqueous ammonium salt in such instances may vary, where mineral alkalinity sources of interest include, but are not limited to: silicates, carbonates, fly ashes, slags, limes, cement kiln dusts, etc., e.g., as described above. In some instances, the mineral alkalinity source comprises a rock, e.g., as described above.

[0087] In embodiments, the alkalinity source is a geomass, e.g., as described in greater detail below.

[0088] While the temperature to which the aqueous ammonium salt is heated in these embodiments may vary, in some instances the temperature ranges from 25 to 200eC, such as 25 to 185SC. The heat employed to provide the desired temperature may be obtained from any convenient source, including steam, a waste heat source, such as flue gas waste heat, etc.

[0089] Distillation may be carried out at any pressure. Where distillation is carried out at atmospheric pressure, the temperature at which distillation is carried out may vary, ranging in some instances from 50 to 120eC, such as 60 to 100eC, e.g., from 70 to 90eC. In some instances, distillation is carried out at a sub-atmospheric pressure. While the pressure in such embodiments may vary, in some instances the sub-atmospheric pressure ranges from 1 to 14 psig, such as from 2 to 6 psig. Where distillation is carried out at sub-atmospheric pressure, the distillation may be carried out at a reduced temperature as compared to embodiments that are performed at atmospheric pressure. While the temperature may vary in such instances as desired, in some embodiments where a sub-atmospheric pressure is employed, the temperature ranges from 15 to 60SC, such as 25 to 50eC. Of interest in sub-atmospheric pressure embodiments is the use of a waste heat for some, if not all, of the heat employed during distillation. Waste heat sources of that may be employed in such instances include, but are not limited to: flue gas, process steam condensate, heat of absorption generated by CO2 capture and resultant ammonium carbonate production; and a cooling liquid (such as from a co- located source of CO2 containing gas, such as a power plant, factory etc., e.g., as described above), and combinations thereof

[0090] Aqueous capture ammonia regeneration may also be achieved using an electrolysis mediated protocol, in which a direct electric current is introduced into the aqueous ammonium salt to regenerate ammonia. Any convenient electrolysis protocol may be employed. Examples of electrolysis protocols that may be adapted for regeneration of ammonia from an aqueous ammonium salt may employed one or more elements from the electrolysis systems described in U.S. Patent Nos. 7,727,374 and 8,227,127, as well as published PCT Application Publication No. WO / 2008 / 018928; the disclosures of which are hereby incorporated by reference.

[0091] In some instances, the aqueous capture ammonia is regenerated from the aqueous ammonium salt without the input of energy, e.g., in the form of heat and / or electric current, such as described above. In such instances, the aqueous ammonium salt is combined with an alkaline source, such as a geomass source, e.g., as described above, in a manner sufficient to produce a regenerated aqueous capture ammonia. The resultant aqueous capture ammonia is then not purified, e.g., by input of energy, such as via stripping protocol, etc.

[0092] The resultant regenerated aqueous capture ammonia may vary, e.g., depending on the particular regeneration protocol that is employed. In some instances, the regenerated aqueous capture ammonia includes ammonia (NH3) at a concentration ranging from 0.1 to 25 moles per liter (M), such as from 4 to 20 M, including from 12.0 to 16.0 M, as well as any of the ranges provided for the aqueous capture ammonia provided above. The pH of the aqueous capture ammonia may vary, ranging in some instances from 10.0 to 13.0, such as 10.0 to 12.5. In some instances, e.g., where the aqueous capture ammonia is regenerated in a geomass mediated protocol that does not include input of energy, e.g., as described above, the regenerated aqueous capture ammonia may further include cations, e.g., divalent cations, such as Ca2+. In addition, the regenerated aqueous capture ammonia may further include an amount of ammonium salt. In some instances, ammonia (NH3) is present at a concentration ranging from 0.05 to 4 moles per liter (M), such as from 0.05 to 1 M, including from 0.1 to 2 M. The pH of the aqueous capture ammonia may vary, ranging in some instances from 8.0 to 11 .0, such as from 8.0 to 10.0. The aqueous capture ammonia may further include ions, e.g., monovalent cations, such as ammonium (NH4+) at a concentration ranging from 0.1 to 5 moles per liter (M), such as from 0.1 to 2 M, including from 0.5 to 3 M, divalent cations, such as calcium (Ca2+) at a concentration ranging from 0.05 to 2 moles per liter (M), such as from 0.1 to 1 M, including from 0.2 to 1 M, divalent cations, such as magnesium (Mg2+) at a concentration ranging from 0.005 to 1 moles per liter (M), such as from 0.005 to 0.1 M, including from 0.01 to 0.5 M, divalent anions, such as sulfate (SO42) at a concentration ranging from 0.005 to 1 moles per liter (M), such as from 0.005 to 0.1 M, including from 0.01 to 0.5 M.

[0093] Aspects of the methods further include contacting the regenerated aqueous capture ammonia with ambient air and / or a gaseous source of CO2, e.g., as described above, under conditions sufficient to produce a CO2 sequestering carbonate, e.g., as described above. In other words, the methods include recycling the regenerated ammonia into the process. In such instances, the regenerated aqueous capture ammonia may be used as the sole capture liquid, or combined with another liquid, e.g., make up water, to produce an aqueous capture ammonia suitable for use as a CO2 capture liquid. Where the regenerated aqueous ammonia is combined with additional water, any convenient water may be employed. Waters of interest from which the aqueous capture ammonia may be produced include, but are not limited to, freshwaters, seawaters, brine waters, produced waters and waste waters.

[0094] Recycling

[0095] In some instances, the methods may include recirculating one or more of the reaction components from one stage of the process to another stage of the process. For example, as described above regenerated aqueous ammonia may be recycled to the CO2 capture stage. Cation salts and / or aggregates produced during ammonia regeneration may be recycled to the carbonate production stage. Waste heat produced at one stage, e.g., CO2 capture, may be employed at another stage, e.g., ammonia regeneration, e.g., as described above. The above are non-limiting examples of embodiments where recycling occurs.

[0096] Production of Pure CO2Gas

[0097] One or more stages of the methods may result in the production of pure CO2 gas. For example, during the production of solid carbonate from the aqueous ammonium carbonate, up to one mol of CO2 may be produced for every 2 mols of ammonium bicarbonate. Alternatively or in addition, the ammonia regeneration step may result in the production of waste CO2. For example, during the ammonia regeneration step, waste C02may come from fugitive CO2lost during heating or may come from alkalinity sources that contained embodied carbonate mineral. While such instances may result in the production of CO2, the overall process sequesters a net amount of CO2in a carbonate compound. Any produced CO2may be substantially pure CO2product gas, which may be sequestered by injection into a subsurface geological location, as described in greater detail below. Therefore, the process is an effective CO2sequestration process. The phrase "substantially pure" means that the product gas is pure CO2or is a CO2containing gas that has a limited amount of other, non-C02components.

[0098] Following production of the CO2product gas in such embodiments, aspects of the invention may include injecting the product CO2gas into a subsurface geological location to sequester CO2. By injecting is meant introducing or placing the CO2product gas into a subsurface geological location. Subsurface geological locations may vary, and include both subterranean locations and deep ocean locations. Subterranean locations of interest include a variety of different underground geological formations, such as fossil fuel reservoirs, e.g., oil fields, gas fields and un-mineable coal seams; saline reservoirs, such as saline formations and saline-filled basalt formations; deep aquifers; porous geological formations such as partially or fully depleted oil or gas formations, salt caverns, sulfur caverns and sulfur domes; etc.

[0099] In some instances, the CO2product gas may be pressurized prior to injection into the subsurface geological location. To accomplish such pressurization the gaseous CO2can be compressed in one or more stages with, where desired, after cooling and condensation of additional water. The modestly pressurized CO2can then be further dried, where desired, by conventional methods such as through the use of molecular sieves and passed to a CO2condenser where the CO2is cooled and liquefied. The CO2can then be efficiently pumped with minimum power to a pressure necessary to deliver the CO2to a depth within the geological formation or the ocean depth at which CO2injection is desired. Alternatively, the CO2can be compressed through a series of stages and discharged as a super critical fluid at a pressure matching that necessary for injection into the geological formation or deep ocean. Where desired, the CO2may be transported, e.g., via pipeline, rail, truck or other suitable protocol, from the production site to the subsurface geological formation.

[0100] In some instances, the CO2product gas is employed in an enhanced oil recovery (EOR) protocol. Enhanced Oil Recovery (abbreviated EOR) is a generic term for techniques for increasing the amount of crude oil that can be extracted from an oil field. Enhanced oil recovery is also called improved oil recovery or tertiary recovery. In EOR protocols, the CO2 product gas is injected into a subterranean oil deposit or reservoir.

[0101] In some embodiments, the CO2 product gas is recovered by contact with aqueous capture ammonia, e.g., as described above, to produce a solid CO2 sequestering carbonate, e.g., as described above. For example, the CO2product gas from one stage of a method may be combined with fugitive aqueous capture ammonia vapor from another, separate stage of a method, to produce aqueous ammonium carbonate that is used in a different stage of a method to produce a solid CO2 sequestering carbonate, e.g., as described above.

[0102] CO2 gas production and sequestration thereof are further described in U.S. Patent No. 10,197,747, the disclosure of which is herein incorporated by reference.

[0103] Alkali Enrichment

[0104] In some instances, the methods further include subjecting the aqueous ammonium carbonate to an alkali enrichment protocol, e.g., a membrane mediated protocol, such as one that includes contacting first and second liquids to opposite sides of a membrane. In such instances, the membrane may be a cationic membrane or an anionic membrane. Further details regarding alkali enrichment protocols, such as membrane mediated alkali enrichment protocols, are described in United States Patent No. 9,707,513; the disclosure of which is herein incorporated by reference. In some such instances, the methods include contacting the aqueous capture ammonia with the gaseous source of CO2 in a combined capture and alkali enrichment reactor, where the reactor may include: a core hollow fiber membrane component, e.g., one that includes a plurality of hollow fiber membranes; an alkali enrichment membrane component surrounding the core hollow fiber membrane component and defining a first liquid flow path in which the core hollow fiber membrane component is present; and a housing configured to contain the alkali enrichment membrane component and core hollow fiber membrane component, wherein the housing is configured to define a second liquid flow path between the alkali enrichment membrane component and the inner surface of the housing. In such instances, the alkali enrichment membrane component may be configured as a tube and the hollow fiber membrane component is axially positioned in the tube. In such instances, the housing may be configured as a tube, wherein the housing and the alkali enrichment membrane component are concentric. Recycling Demolished and Remediated Concrete

[0105] In some aspects of the invention, the methods further include providing calcium and / or alkalinity into one or more steps of the process from demolished or returned concrete geomass for carbon sequestration and utilization through calcium carbonate mineralization and use of the residual or remediated concrete as a favorable aggregate in new concrete after the partial dissolution of recycled concrete geomass material. Geomass or geomass material, as used herein, refers to concrete that has been returned from a job site or demolished and crushed after its service life or other reasons. Though generally, geomass is most commonly a waste product from industry, geomass may also refer to primary, secondary, tertiary, byproduct or other product from industry. Some example general trade names of geomass materials from industry may include mine tailings, mining dust, sand, baghouse fines, soil dust, dust, cement kiln dust, slag, steel slag, iron slag, boiler slag, coal combustion residue, ash, fly ash, slurry, lime slurry, lime, kiln dust, kiln fines, residue, bauxite residue, demolished concrete, returned concrete, crushed concrete, recycled concrete, recycled mortar, recycled cement, demolished building materials, recycled building materials, recycled aggregate, etc. Geomass materials typically have compositions that contain metal oxides, as crystalline or amorphous phases, such as sodium oxide, potassium oxide, or other alkali metal oxide, magnesium oxide, calcium oxide, or other alkaline earth metal oxide, manganese oxide, copper oxide, or other transition metal oxide, zinc oxide or any other metal oxide or derivative thereof, or metal oxides present in crystalline form in simple or complex minerals or as amorphous phases of metal oxides or derivatives thereof or as a combination of any of the above.

[0106] Embodiments described herein include methods of reducing transportation distance of aggregate by recycling demolished concrete and using the residual material remaining after geomass dissolution as aggregate in new concrete. The use of remediated concrete geomass as aggregate in new concrete reduces both the price and carbon footprint associated with the concrete. For example, if a concrete geomass contains 60% by weight calcium oxide (CaO) cement, and the cement is 10% of the concrete geomass, then 100% dissolution efficiency of CaO would result in 6% of the mass of the concrete geomass being dissolved for carbon capture and utilization, leaving the remaining 94% for utilization as recycled aggregate in new concrete, using the methods of invention. As such, aspects of the subject methods include dissolution efficiency of metal oxides present in the geomass to 0.05% or greater, such as 1.1% or greater, e.g., 2.1% or greater, 3.1 % or greater, 4.1% or greater, 5.1% or greater, 6.1 % or greater, 7.1% or greater, 8.1% or greater, 9.1% or greater, including 10% or greater, 20% or greater, 30% or greater, 40% or greater, 50% or greater, 60% or greater, 70% or greater, 80% or greater, 90% or greater and up to 100% dissolution efficiency. Additional aspects of embodiments the subject methods include liberating as individual particles present in the concrete geomass to 0.05% or greater, such as 1.1% or greater, e.g., 2.1 % or greater, 3.1% or greater, 4.1 % or greater, 5.1% or greater, 6.1% or greater, 7.1 % or greater, 8.1% or greater, 9.1 % or greater, including 10% or greater, 20% or greater, 30% or greater, 40% or greater, 50% or greater, 60% or greater, 70% or greater, 80% or greater, 90% or greater and up to 100% of the original sand and gravel aggregates in the demolished concrete in a form similar to their original virgin characteristic, useful in concrete, unlike mechanically crushed and classified recycled concrete.

[0107] Aspects of the methods include utilizing the remediated concrete aggregate as a substrate for applying a carbonate mineral coating derived from capture carbon dioxide for permanent sequestration in the mineral phase, e.g., as described above, creating a composite aggregate useful as an aggregate for concrete. This method of obtaining a substrate for the mineral coating similarly has the advantage of avoiding mining and transportation of fresh virgin aggregate.

[0108] Aspects of the methods include formulating concrete, mortar, and asphalt using the remediated residual concrete aggregate materials, either alone or coated with a CO2 sequestered carbonate mineral. The amount of remediated coated or uncoated aggregate particles in the concrete, mortar, or asphalt may be present in the amounts of to 0.05% or greater, such as 1 .1% or greater, e.g., 2.1% or greater, 3.1% or greater, 4.1 % or greater, 5.1% or greater, 6.1 % or greater, 7.1% or greater, 8.1% or greater, 9.1 % or greater, including 10% or greater, 20% or greater, 30% or greater, 40% or greater, 50% or greater, 60% or greater, 70% or greater, 80% or greater, 90% or greater and up to 100% of the original sand and gravel aggregates in the concrete, mortar, or asphalt in a form similar to their original virgin characteristic, useful in concrete, unlike mechanically crushed and classified recycled concrete.

[0109] The dissolution of a variety of concrete and mortar materials may be useful and the residual remediated aggregate may be used in a large array of building material application, including all the uses of mined aggregates. Concrete and mortar materials, and any materials comprising Portland cement are of interest including at least those materials coming from roadways, buildings, dams, bridges, sidewalks, piping, culverts, water conductance systems, well casings, and the like.

[0110] Demolished concrete may be obtained from a variety of different sources, including but not limited to buildings, roads, pavements, sidewalks, barriers, and other structures. The source of returned concrete may come from a variety of sources, including but not limited to the ready-mix concrete trucks returning to their plant from a job site with unused or returned concrete. The source may be demolished using any convenient protocol to produce demolished geomass. The demolished geomass may then be employed in one or more stages of a CO2 sequestering solid carbonate production process, e.g., as described above, to produce one or more types of products, including remediated building compositions, which may be employed in a variety of markets, including construction markets.

[0111] The above described embodiment of recycling demolished and / or returned and remediated concrete is not limited to particular gaseous sources of CO2. Instead, the above described embodiment of recycling demolished and remediated concrete may be employed with processes employing any convenient gaseous source of CO2, such as waste streams produced by industrial plants that combust fossil fuels, e.g., coal, oil, natural gas, as well as man-made fuel products of naturally occurring organic fuel deposits, such as but not limited to tar sands, heavy oil, oil shale, etc. In certain embodiments, power plants are pulverized coal power plants, supercritical coal power plants, mass burn coal power plants, fluidized bed coal power plants, gas or oil-fired boiler and steam turbine power plants, gas or oil-fired boiler simple cycle gas turbine power plants, and gas or oil-fired boiler combined cycle gas turbine power plants, where methods employing such sources are further described in: U.S. Patent Nos. 9,707,513; 9,714,406; 9,993,79910,71 1 ,236; 10,203,434; 10,197,747; the disclosures of which are herein incorporated by reference.

[0112] Enhanced Geomass Dissolution Methods

[0113] Where the methods include dissolving geomass, e.g., as described above, aspects of the methods may include enhancing the dissolution of geomass, where a geomass and a liquid phase are combined in a system under conditions sufficient to produce a desired dissolution efficiency. Aspects of these embodiments further include systems configured to produce dissolved geomass compositions, and methods and devices that include the same. Also provided are methods that use dissolved geomass compositions.

[0114] As reviewed above, geomass or geomass material, as used herein, refers to industry products from industries such as mining industry, power industry, and heavy industry. Though most commonly a waste product from industry, geomass may also refer to primary, secondary, tertiary, byproduct or other product from industry. Some example trade names of geomass materials from industry may include mine tailings, mining dust, sand, bag house fines, soil dust, dust, cement kiln dust, slag, steel slag, iron slag, boiler slag, coal combustion residue, coal combustion product, ash, fly ash, slurry, lime slurry, lime, carbide lime, carbide residue, kiln dust, kiln fines, residue, bauxite residue, demolished concrete, recycled concrete, returned concrete, recycled mortar, recycled cement, demolished building materials, recycled building materials, recycled aggregate, etc. Geomass materials typically have compositions that contain metal oxides, as crystalline or amorphous phases, such as sodium oxide, potassium oxide, or other alkali metal oxide, magnesium oxide, calcium oxide, or other alkaline earth metal oxide, manganese oxide, copper oxide, or other transition metal oxide, zinc oxide or any other metal oxide or derivative thereof, or metal oxides present in crystalline form in simple or complex minerals or as amorphous phases of metal oxides or derivatives thereof or as a combination of any of the above.

[0115] As the methods are methods of enhancing geomass dissolution, the methods result in the leaching, seeping, straining, liberation, etc., of metal oxides or minerals from the geomass into a liquid phase such as an aqueous phase or an organic phase or as a combination of any other liquid phases, up to 100% dissolution efficiency of the desired metal oxides present in the composition of the geomass (as compared to a suitable control, e.g., the geomass material not subjected to methods of invention). For example, if a geomass contains 25% by weight calcium oxide (CaO), then 100% dissolution efficiency of CaO would result in 25% of the mass of the geomass being dissolved using the methods of invention. As such, aspects of the subject methods include dissolution efficiency of metal oxides present in the geomass to 0.05% or greater, such as 1.1% or greater, e.g., 2.1% or greater, 3.1 % or greater, 4.1% or greater, 5.1% or greater, 6.1 % or greater, 7.1% or greater, 8.1% or greater, 9.1% or greater, including 10% or greater, 20% or greater, 30% or greater, 40% or greater, 50% or greater, 60% or greater, 70% or greater, 80% or greater, 90% or greater and up to 100% dissolution efficiency. In some embodiments, the methods use microwave radiation to enhance the dissolution efficiency of a geomass. Microwaves, microwave radiation, microwave energy, etc., are a form of non-ionizing electromagnetic radiation energy with wavelengths ranging from one meter (1 m) to one millimeter (1 mm), a frequency higher than ordinary radio waves but lower than infrared light, with frequencies that range, e.g., from 300 megahertz (MHz) to 300 gigahertz (GHz). Microwave radiation has been investigated to improve dissolution efficiency in order to improve overall yield and process time. Microwave radiation offers advantages over conventional heating that involve, non-contact heating, transfer of energy (not heat), rapid heating, material selective heating, volumetric heating, quick starting and stopping of heating, heating starting from interior, and improved safety. The microwave radiation that is employed in methods of the invention may vary according to process specificity, so long as it provides the desired enhancement in dissolution efficiency of the geomass. By microwaves, microwave radiation, microwave energy, etc., is meant a form of energy with frequencies that vary, and in some instances may range from 500 MHz to 100 GHz, such as 900 MHz to 5 GHz and including from 300 MHz to 300 GHz or the full microwave spectrum of frequencies. The methods use microwaves, microwave radiation, microwave energy, etc., to provide the power necessary to enhance the dissolution efficiency of the geomass, which may vary, and in some instances may range from one watt (1 W) to one gigawatt (1 GW), such as one kilowatt (1 kW) to one megawatt (1 MW) and including from 500 kW to 500 MW.

[0116] Aspects of the methods include microwave treatment of a combination of geomass material with a liquid phase to enhance the dissolution efficiency of the geomass. The treatment may occur, but is not limited to occurring in, a vessel or device that operates continuously, in batch, or a combination thereof. In certain embodiments, the geomass materials are present as particles that vary in size, e.g., with particle sizes ranging from 0.1 microns to several inches in diameter, e.g., 1 micron to 20 inches, or 100 microns to 10 inches, or 500 microns to 20 inches, in some embodiments 25 microns to 3 / 8 inches. In some embodiments, the liquid phase used in the methods is an aqueous medium, an organic medium, a combination thereof, or any other liquid medium that helps to promote the enhanced dissolution efficiency of the geomass using methods, systems and devices herein.

[0117] As the methods are methods of enhanced geomass dissolution efficiency, the microwave treatment or dielectric heating mechanism of enhancement is considered as methods, systems and devices described herein. The rate of geomass materials dissolution involves the surface area, the composition of the geomass itself, which may be comprised of many different mineral phases, and the temperature of the system, which may depend on the penetration of microwave radiation, effectiveness of dielectric heating, etc. Dielectric heating is a method in which a high frequency alternating electric field or radiofrequency or microwave electromagnetic radiation heats a material with dielectric properties. Dielectric heating is enhanced by materials with a dipole moment that are capable of molecular rotation, i.e., H2O, molecules with carboxylic acid or carboxylate groups such as, but not limited to acetate, oxalate, glutamate, malate or other organic or natural carboxylic acid or carboxylate containing molecule. Molecules attempt to reorient themselves in the electric field and cannot respond to friction, therefore creating a stronger heating effect. The stronger heating effect described in this method is a localized method that enhances the dissolution of the different phases contained in the geomass.

[0118] The heating effect caused by microwave radiation in the enhanced methods described herein may also lower the heat requirements for a carbon sequestration method that uses the enhanced dissolution methods as part of its process to capture and sequester carbon dioxide. For example, the enhanced methods may reduce the auxiliary power requirement for carbon sequestration methods, reducing the parasitic load associated with the auxiliary power requirement. The enhanced dissolution methods may lower or even reduce the need for a heat source such as heat from steam or heat from electrical power that are sometimes necessary to drive carbon sequestration methods, devices and systems.

[0119] Instead of or in addition to use of microwaves, e.g., as described above, enhancement of dissolution efficiency of geomass material may involve mixing or heating the geomass material in a liquid phase that contains ammonium salts, acidic media, surfactants or catalysts that can be regenerated in a batch or continuous flow process.

[0120] Dissolution efficiency described in this method can be enhanced by liquid phase solutions containing organic or inorganic materials with a dipole moment that ranges between 0 and 80 Debye, such as materials with a dipole moment of 0.01 Debye or greater, 0.1 Debye or greater, 1 .0 Debye or greater such as a dipole moment that ranges between 0.5 and 0.9 Debye, and including materials with a dipole moment of 2.0 Debye or greater, 3.0 Debye or greater, 4.0 Debye or greater. The solution employed in this method may further include a catalyst, an organic ligand, or a surfactant. The solution employed may contain an organic salt or organic acid with a dipole moment to enhance dielectric heating efficiency of heating. The solution may be optimized to reduce reflection that decreases the efficiency of the microwave energy penetration. The solution in this method is optimized to generate a homogenous temperature, which improves the heating efficiency of the solution and dissolution efficiency of this material.

[0121] The dissolution of a variety of geomass materials may be enhanced. Geomass materials of interest include at least those materials coming from power industry, heavy industry and mining industry. Geomass generated as a waste product in the production of primary industry products (e.g., mined minerals, electricity, steel, cement, alumina) from a variety of industries (e.g., the mining industry, power industry, heavy industry) is dissolved using an enhanced dissolution method, e.g., a microwave mediated dissolution method, such as described above. The dissolved geomass and mother liquor may then be employed in one or more stages of a CO2 sequestering solid carbonate production process, e.g., as described above, to produce one or more types of solid carbonate products, which may be employed in a variety of markets, including construction markets. As illustrated, the mother liquor may be recycled into the dissolution method, as desired. Undissolved geomass may also be employed in construction markets, e.g., as aggregate, etc.

[0122] The above described embodiment of enhancing geomass dissolution is not limited to embodiments particular gaseous sources of CO2. Instead, the above described embodiment of geomass dissolution may be employed with processes employing any convenient gaseous source of CO2, such as waste streams produced by industrial plants that combust fossil fuels, e.g., coal, oil, natural gas, as well as man-made fuel products of naturally occurring organic fuel deposits, such as but not limited to tar sands, heavy oil, oil shale, etc. In certain embodiments, power plants are pulverized coal power plants, supercritical coal power plants, mass burn coal power plants, fluidized bed coal power plants, gas or oil-fired boiler and steam turbine power plants, gas or oil-fired boiler simple cycle gas turbine power plants, and gas or oil-fired boiler combined cycle gas turbine power plants, where methods employing such sources are further described in: U.S. Patent Nos. 9,707,513; 9,714,406; 9,993,79910,71 1 ,236; 10,203,434; 10,197,747; the disclosures of which are herein incorporated by reference. SYSTEMS FOR SEQUESTERING CO2FROM AMBIENT AIR

[0123] As discussed above, aspects of the invention also include systems. Systems of interest include a CO2sequestration unit configured to directly contact an aqueous capture liquid with the ambient air and produce CO2-depleted air. Systems of the invention include functional modules or reactors, e.g., as described above, that are operatively coupled in a manner sufficient to perform methods of the invention, e.g., as described above. By “CO2 sequestration unit”, it is meant a device configured to contact ambient air with a capture liquid. The CO2 sequestration unit may carry out this contacting in any convenient manner. In some embodiments, the CO2 sequestration unit is configured to contact the aqueous capture liquid with the ambient air in a countercurrent manner. In other embodiments, the CO2sequestration unit is configured to contact the aqueous capture liquid with the ambient air in a co-current manner. In still other embodiments, the CO2sequestration unit is configured to contact the aqueous capture liquid with the ambient air in a cross-current manner. In some instances, the CO2 sequestration unit comprises a hollow fiber membrane contactor. In some instances, the CO2 sequestration unit comprises a regenerative froth contactor. In some instances, the CO2sequestration unit contains a combination of contactors, e.g., as described above, in different arrangements.

[0124] In some embodiments, the CO2sequestration unit is not configured to concentrate the CO2 from the ambient air prior to contacting it with the aqueous capture liquid. In some such embodiments, the CO2 sequestration unit is not configured to perform direct air capture (DAC). In other words, the CO2 sequestration unit is not configured to subject ambient air to a hydroxide-based DAC process or a CO2 sorbent / temperature swing based DAC process. As such, the amount of CO2 in the ambient air used in the CO2 sequestration unit is the same as the surrounding environment.

[0125] In some instances, the CO2 sequestration unit comprises a combined capture and alkali enrichment reactor, the reactor comprising: a core hollow fiber membrane component (e.g., one that comprises a plurality of hollow fiber membranes); an alkali enrichment membrane component surrounding the core hollow fiber membrane component and defining a first liquid flow path in which the core hollow fiber membrane component is present; and a housing configured to contain the alkali enrichment membrane component and core hollow fiber membrane component, wherein the housing is configured to define a second liquid flow path between the alkali enrichment membrane component and the inner surface of the housing. In some instances, the alkali enrichment membrane component is configured as a tube and the hollow fiber membrane component is axially positioned in the tube. In some instances, the housing is configured as a tube, wherein the housing and the alkali enrichment membrane component are concentric. Aspects of the invention further include a combined capture and alkali enrichment reactor, e.g., as described above.

[0126] In certain cases, systems of the invention include a gas conveyor configured to draw the ambient air into the CO2 sequestration unit from a surrounding environment and contact the ambient air with the capture liquid. In certain versions, the gas conveyor is an air pump. In other cases, the gas conveyor is a compressor. In still other cases, the gas conveyor is a turbine. In some instances, the gas conveyor is powered by a source of green energy. In select embodiments, the source of green energy is selected from wind energy, hydroelectric energy, solar energy, geothermal energy, nuclear energy and the like, as well as combinations thereof. In certain versions, the source of green energy is wind energy. In other versions, the source of green energy is hydroelectric energy. In still other versions, the source of green energy is solar energy. In yet other versions, the source of green energy is geothermal energy. In still other embodiments, the source of green energy is nuclear energy.

[0127] In some instances, the CO2 sequestration unit is gaseously connected to a point source of gaseous CO2 configured to produce a CO2-containing gas. Any convenient point source of gaseous CO2may be employed, including those described above. In some embodiments, the point source of gaseous CO2is comprised of a power plant. In other embodiments, the power plant is a combined cycle power plant. In some cases where the system includes a gas conveyor comprised of a turbine, the turbine may be used to power the point source of gaseous CO2, thereby generating the CO2. In some cases, the point source of gaseous CO2comprises the turbine (i.e., the turbine is a constituent part of the point source of gaseous CO2). In some cases, the turbine is configured for combustion of a fuel (e.g., a natural gas) to generate electricity and produce the C02-containing gas.

[0128] In embodiments, the subject systems include a control unit operably connected to the point source of gaseous CO2. The control unit may have instructions stored thereon which, when executed by the control unit, are configured to carry out select methods of the invention. For example, in some cases, the control unit may be configured to cause: (a) the gas conveyor to draw in the C02-containing gas from the point source of gaseous CO2, (b) the CO2 sequestration unit to contact the CO2- containing gas with the aqueous capture liquid, (c) the point source of gaseous C02to cease providing the CC>2-containing gas to the CO2 sequestration unit, and (d) the gas conveyor to resume or continue drawing in the ambient air. In select instances, the control unit is configured to activate and deactivate the point source of gaseous CO2.

[0129] Control units according to some embodiments of the invention are configured to cyclically repeat steps (a)-(d). These steps may be repeated any number of times. For example, in some cases, steps (a)-(d) are repeated 2 or more times, 10 or more times, 50 or more times, 100 or more times, 500 or more times, 1000 or more times, 5000 or more times, 10000 or more times, 50000 or more times and including 1000000 or more times. In some cases, control units are configured to cyclically repeat steps (a)-(d) an indefinite number of times. In select instances, control units repeat steps (a)-(d) according to a cyclical availability of green energy. In other words, the performance of the steps are at least partially determined by whether the green energy is available at a given time (e.g., as discussed above).

[0130] In some instances, the control units are operated in conjunction with programmable logic that may be implemented in hardware, software, firmware, or any combination thereof in order to carry out one or more steps of the subject methods. The subject programmable logic may be implemented in any of a variety of devices such as specifically programmed computers, wireless communication devices, integrated circuit devices, or the like. In some embodiments, the programable logic may be executed by a specifically programmed processor, which may include one or more processors, such as one or more digital signal processors (DSPs). A combination of computing devices may also implement one or more of the features described herein.

[0131] The processor may include a general-purpose digital microprocessor suitably programmed from a computer readable medium carrying necessary program code. Programming can be provided remotely to the processor through a communication channel, or previously saved in a computer program product such as memory or some other portable or fixed computer readable storage medium using any of those devices in connection with memory. For example, a magnetic or optical disk may carry the programming, and can be read by a disk writer / reader. Systems of the invention also include programming, e.g., in the form of computer program products, algorithms for use in practicing the methods as described above. Programming according to the present invention can be recorded on computer readable media, e.g., any medium that can be read and accessed directly by a computer. Such media include, but are not limited to: magnetic storage media, such as floppy discs, hard disc storage medium, and magnetic tape; optical storage media such as CD-ROM; electrical storage media such as RAM and ROM; portable flash drive; and hybrids of these categories such as magnetic / optical storage media. In some embodiments, control units are implemented using an operating system. Various operating systems may be employed, possibly depending on the type and / or make of computer platform chosen. Appropriate operating systems include Windows® NT®, Windows® XP, Windows® 7, Windows® 8, Windows® 10, iOS®, macOS®, Linux®, Ubuntu®, Fedora®, OS / 400®, i5 / OS®, IBM i®, Android™, SGI IRIX®, Oracle Solaris® and others.

[0132] FIG. 2A-2B depict a system of the invention according to certain embodiments. FIG. 2A shows system 200 sequestering CO2 from ambient air. A gas conveyor (i.e., turbine 202) draws in ambient air from the surrounding environment by driving turbine 202 using energy 203, which is optionally green energy. The drawn in ambient air is provided to CO2 sequestration unit 204, which captures the CO2and releases CO2 depleted air. In the example of FIG. 2A, turbine 202 is a component of point source of CO2 201 , which is inactive (e.g., it is not generating power and / or a manufactured product). In FIG. 2B, control unit 205 has activated point source of CO2 201 . Control unit 205 also causes the combustion of a fuel to drive turbine 202, thereby generating energy 206. In a case where point source of CO2 201 is an industrial plant, energy 206 may be employed to power the industrial plant. Where point source of CO2201 is a power plant, energy 206 may be supplied, e.g., to the electrical grid. CO2 produced from the combustion of the fuel is provided CO2 sequestration unit 204, which captures the CO2 and releases CO2 depleted air.

[0133] In some embodiments, systems also include a source of waste heat gaseously connected to the CO2 sequestration unit. Any convenient source of waste heat may be included. Sources of waste heat include, but are not limited to machinery, computers, homes, and the like. In some cases, the source of waste heat is a data center. In select instances, the system is configured to gaseously cool the source of waste heat via a heating, ventilation, and air conditioning (HVAC) system of the source of waste heat. In some such instances, the gas conveyor is configured to move air through the HVAC system and thereby cool the components associated with the HVAC system. The ambient air may be used to cool the source of waste heat before or after said air is contacted with the capture liquid. In some embodiments, systems are configured to contact the ambient air with the source of waste heat prior to the contact of the ambient air with the capture liquid. In other embodiments, systems are configured to contact the CC>2-depleted air with the source of waste heat.

[0134] FIG. 3A-3B depict embodiments of the subject systems that are configured to cool a source of waste heat, depicted as data center 301 . FIG. 3A depicts a system configured to contact the ambient air with the source of waste heat prior to the contact of the ambient air with the capture liquid. As shown in FIG. 3A, ambient air comprising CO2 is drawn in from the surrounding environment by rotating turbine 302 and enters HVAC system 301 a of data center 301 . Said air in HVAC system 301 a is used to cool server racks 301 b, and is then provided to CO2 sequestration unit 204. FIG. 3B includes the same components rearranged such that the system is configured to contact the CO2- depleted air with the source of waste heat.

[0135] In embodiments, systems of the invention are configured to directly contact an aqueous capture liquid comprising an aqueous capture ammonia with the ambient air and produce a CO2 sequestering carbonate and an aqueous ammonium salt. In some such embodiments, operably coupled to the CO2 sequestration unit is a carbonate production module. Embodiments of modules include continuous reactors that are configured for producing CO2 sequestering carbonate materials. As the systems include continuous reactors (i.e., flow reactors), they include reactors in which materials are carried in a flowing stream, where reactants (e.g., divalent cations, aqueous bicarbonate rich liquid, etc.) are continuously fed into the reactor and emerge as continuous stream of product. The continuous reactor components of the systems are therefore not batch reactors. A given system may include the continuous reactors, e.g., as described herein, in combination with one or more additional elements, as described in greater detail below.

[0136] In some embodiments, continuous reactors of the systems include: a flowing aqueous liquid, e.g., an aqueous ammonium carbonate; a divalent cation introducer configured to introduce divalent cations at an introduction location into the flowing aqueous liquid; and a non-slurry solid phase CO2sequestering carbonate material production location which is located at a distance from the divalent cation introducer. The flowing aqueous liquid is a stream of moving aqueous liquid, e.g., as described above, which may be present in the continuous reactor, where the continuous reactor may have any convenient configuration. Continuous reactors of interest include an inlet for a liquid and an outlet for the waste liquid, where the inlet and outlet are arranged relative to each other to provide for continuous movement or flow of the liquid into and out of the reactor. The reactor may have any convenient structure, where in some instances the reactor may have a length along which the liquid flows that is longer than any given cross sectional dimension of the reactor, where the inlet is at a first end of the reactor and the outlet is at a second end of the reactor. The volume of the reactor may vary, ranging in some instances from 10 L to 1 ,000,000 L, such as 1 ,000 L to 100,000 L.

[0137] Continuous reactors of interest further include a divalent cation introducer configured to introduce divalent cations at an introduction location into the flowing aqueous liquid. Any convenient introducer may be employed, where the introducer may be a liquid phase or solid phase introducer, depending on the nature of the divalent cation source. The introducer may be located in some instances at substantially the same, if not the same, position as the inlet for the bicarbonate rich product containing liquid. Alternatively, the introducer may be located at a distance downstream from the inlet. In such instances, the distance between the inlet and the introducer may vary, ranging in some embodiments from 1 cm to 10 m, such as 10 cm to 1 m. The introducer may be operatively coupled to a source or reservoir of divalent cations.

[0138] Continuous reactors of interest also include a non-slurry solid phase CO2 sequestering carbonate material production location. This location is a region or area of the continuous reactor where a non-slurry solid phase CO2 sequestering carbonate material is produced as a result of reaction of the divalent cations with bicarbonate ions of the bicarbonate rich product containing liquid. The reactor may be configured to produce any of the non-slurry solid phase CO2 sequestering carbonate materials described above in the production location. In some instances, the production location is located at a distance from the divalent cation introduction location. While this distance may vary, in some instances the distance between the divalent cation introducer and the material production location ranges from 1 cm to 10 m, such as 10 cm to 1 m.

[0139] The production location may include seed structure(s), such as described above. In such instances, the reactor may be configured to contact the seed structures in a submerged or non-submerged format, such as described above. In non-submerged formats, the flowing liquid may be present on the surface of seed structures as a layer, e.g., of varying thickness, but a gas, e.g., air, separates at least two portions of the seed structure, e.g., two different particles, such that the particles are not submerged in the liquid. Further details regarding such reactors that may be employed as carbonate production modules in embodiments of the present systems are provide in U.S. Patent No. 9,993,799; the disclosure of which is herein incorporated by reference.

[0140] In embodiments, systems include a reformer configured to regenerate the aqueous capture ammonia from the aqueous ammonium salt. The reformer may vary so long it is configured to produce ammonia from the aqueous ammonium salt, e.g., via distillation or electrolysis, or through a process that does not introduce energy, such as described above. In some instances, the reformer will be configured to operate a sub- atmospheric pressure, e.g., as described above, such that it will include one or more components for producing sub-atmospheric pressure, e.g., pumps, etc. In some instances, the reformer is operably coupled to a source of generated heat, e.g., steam, and / or one or more sources of waste heat, e.g., as described above. In some embodiments, the regeneration module includes a source of alkalinity, such as a mineral alkali source, e.g., as described above. In some instances, the system is configured to recycle regenerated aqueous capture ammonia to the CO2 gas / aqueous capture ammonia module, e.g., as described above.

[0141] In some instances, the systems and modules thereof are industrial scale systems, by which is meant that they are configured to process industrial scale amounts / volumes of input compositions (e.g., gases, liquids, solids, etc.). For example, the systems and modules thereof, e.g., CO2 contactor modules, carbonate production modules, ammonia regeneration modules, etc., are configured to process industrial scale volumes of liquids, e.g., 1 ,000 gal / day or more, such as 10,000 gal / day or more, including 25,000 gal / day or more, where in some instances, the systems and modules thereof are configured to process 1 ,000,000,000 gal / day or less, such as 500,000,000 gal / day or less. Similarly, the systems and modules thereof, e.g., CO2 contactor modules, etc., are configured to process industrial scale volumes of gases, e.g., 25,000 cubic feet / hour or more, such as 100,000 cubic feet / hour or more, including 250,000 cubic feet / hour or more, where in some instances, the systems and modules thereof are configured to process 500,000,000 cubic feet / hour or less, such as 100,000,000 cubic feet / hour or less.

[0142] In some embodiments, a system is in fluidic communication with a source of aqueous media, such as a naturally occurring or man-made source of aqueous media, and may be co-located with a location where a CO2 sequestration protocol is conducted. The systems may be present on land or sea. For example, a system may be a land based system that is in a coastal region, e.g., close to a source of sea water, or even an interior location, where water is piped into the system from a salt water source, e.g., an ocean. Alternatively, a system may be a water based system, i.e., a system that is present on or in water. Such a system may be present on a boat, ocean-based platform etc., as desired. In certain embodiments, a system may be co-located with an industrial plant, e.g., a power plant, at any convenient location.

[0143] FIG. 4 provides a schematic representation of a system 400 according to an embodiment of the invention comprising a reactor configured to combine cations from a cation source and the aqueous ammonium carbonate, and is configured to regenerate the aqueous capture ammonia from the aqueous ammonium salt via distillation such that the embodiment of FIG. 4 may be described as a “hot process”. As shown in system 400, ambient air and / or a CO2 containing gas from a gas conveyor of the invention (i.e., turbine 420, described above) and an aqueous ammonia capture liquid (NH3(aq)) are combined in CO2 sequestration unit 401 , which results in the production of CC>2-depleted gas 408 and aqueous ammonium carbonate (NH4)2CO3(aq). The aqueous ammonium carbonate is then combined with aqueous calcium chloride (CaCl2(a)) and aqueous ammonium chloride (NH4CI(aq)), as well as upcycled geomass 406 in reactor 402. In addition to an aggregate product 410, the reactor 402 yields aqueous ammonium salt, specifically aqueous ammonium chloride (NH4CI(aq)), which aqueous ammonium salt is then conveyed to reformer 404. In reformer 404, the aqueous ammonium salt is combined with a solid geomass 407 (CaO(s)) to yield geomass aggregate which may be upcycled and an initial regenerated aqueous ammonia liquid, which includes aqueous ammonia (NH3(aq)), aqueous calcium chloride (CaCl2(aq)) and aqueous ammonium chloride (NH4CI(aq)). The initial regenerated aqueous ammonia liquid is then conveyed to a stripper module 403, where heat provided by steam is employed to distill aqueous ammonia (NH3(aq)) capture liquid from the initial regenerated liquid. Inputs to system 400 also include steam and power 414, and water 415. Outputs to system 400 also include wastewater 413. (It is noted that, in FIG. 4, chemical equations are not balanced and are for illustrative purposes only).

[0144] FIG. 5 provides a schematic diagram of system 500 in which no steam stripping or high-pressure systems are employed, such that the process depicted may be viewed as a cold process. As shown in FIG. 5, ambient air and / or a CO2 containing gas from a gas conveyor of the invention (i.e., turbine 520, described above) is combined with an aqueous ammonia (NH3(aq)) capture liquid that also includes aqueous calcium chloride (CaCl2(aq)) and aqueous ammonium chloride (NH4CI(aq)) in CO2 sequestration unit 501 , which results in the production of CO2 depleted gas 508 and a calcium carbonate slurry (CaCO3(s)). In the CO2 sequestration unit 501 , a suspension from reformer 504 either as an aqueous solution with suspended solids or as an aqueous solution free from solids, is contacted directly with ambient air and / or a CO2 containing gas from turbine 520 thereby producing solid calcium carbonate (CaCOs) inside the unit. In CO2 sequestration unit 501 , the pH may be basic, in some instances 9 or higher, the aqueous ammonia (or alkalinity) concentration may be 0.20 mol / L or higher and the calcium ion concentration may be 0.10 mol / L or higher. The temperature in CO2 sequestration unit 501 may vary, in some instances ranging from 10 to 40, such as 15 to 35 °C, where in some instances the temperature is ambient temperature or lower, ranging from 2 to 10, such as 2 to 5 °C. In some instances the aqueous ammonia capture liquid feeding into the CO2 sequestration unit 501 is cooled using a heat source, e.g., a waste heat source, such as hot flue gas from a power plant, and principles of adsorption or absorption, e.g., using an adsorption or absorption refrigerator or chiller that, with a heat source input, provide the energy needed to drive the cooling process.

[0145] With respect to the calcium carbonate slurry produced by CO2 sequestration unit 501 , in some instances, the slurry precipitated calcium carbonate has no detectable calcite morphology, and may be amorphous (ACC), vaterite, aragonite or other morphology, including any combination of such morphologies. The resultant calcium carbonate slurry is then conveyed to reactor 502, where it is combined with upcycled geomass 506 (e.g., from reformer 504) and / or new aggregate substrate to produce an agglomerated aggregate product 510 that includes a CO2 sequestering carbonate material. In reactor 502, the CaCOs slurry from CO2 sequestration unit 501 is processed to produce aggregate rocks for concrete, either as pure CaCOs rocks or as a mixture of CaCOs and geomass dust / superfine material. In addition to the calcium carbonate slurry (CaCC>3(s)), the CO2 sequestration unit 501 also produces aqueous ammonium chloride (NH4CI(aq)), which aqueous ammonium chloride (NH4CI(aq)) is then conveyed to reformer 504. In reformer 504, the aqueous ammonium chloride (NH4CI(aq)) is combined with a solid geomass 507 (CaO(s)) to yield geomass aggregate 505 which may be upcycled and a regenerated aqueous ammonia liquid, which includes aqueous ammonia (NH3(aq)), aqueous calcium chloride (CaCh(a)) and aqueous ammonium chloride (NH4CI(aq)). In reformer 504, metal oxides, e.g., calcium oxide (CaO), are extracted by mixing geomass with an aqueous ammonium chloride (NH4CI) solution from CO2 sequestration unit 501 , resulting in partial reformation of ammonium (NH4+) ions into aqueous ammonia (NH3) and in dissolution of calcium (Ca2+) ions from the geomass. The regenerated aqueous ammonia liquid is then conveyed to CO2 sequestration unit 501 . (It is noted that, in FIG. 5, chemical equations are not balanced and are for illustrative purposes only). Inputs to system 500 also include power 514, and water 515. Outputs to system 500 also include wastewater 513.

[0146] Where desired, e.g., to remove and recover chemical species, e.g., ammonium chloride (NH4CI), calcium ions, aqueous ammonia, etc., from the surfaces and pores of the reformed geomass and from the calcium carbonate (CaCOs) slurry, the materials may be washed using one or more of the following techniques before final dewatering: (a) steaming, e.g., using low grade steam, waste heat from hot flue gas, etc., in a humidity chamber, etc.; (b) soaking, e.g., letting low salinity water diffuse into pores of aggregates so as to extract the desirable chemical species; (c) sonication, e.g., applying ultrasonic frequencies to continuous or batch processes so as to shock the aggregates into releasing desirable chemical species; and (d) chemical additions, e.g., using additives to chemically neutralize the aggregates.

[0147] In some instances the, the above protocols are carried out using a system of one or more shippable modular units configured for use in sequestering CO2, e.g., as described in PCT published application No. WO 2016 / 160612; the disclosure of which is herein incorporated by reference. Aspects of the units include a support, e.g., a housing or base, having associated therewith one or more of: a CO2 gas / liquid contactor subunit, a carbonate production subunit, an alkali enrichment subunit, a water softening subunit, a cation recovery subunit, a heat exchange subunit, a reverse osmosis subunit, a nanofiltration subunit, a microfiltration subunit, an ultrafiltration subunit, and a purified CO2 collection subunit. Modular units configured for use in the present invention may also include an ammonia regeneration unit, e.g., as described above. Also provided are systems made up of one or more such modular units. Systems disclosed herein include large capacity systems, where individual modular units may contain only one type or more of a given subunit, e.g., a CO2 gas / liquid contactor subunit, a carbonate production subunit, an alkali enrichment subunit, a water softening subunit, a cation recovery subunit, a heat exchange subunit, a reverse osmosis subunit, a nanofiltration subunit, a microfiltration subunit, an ultrafiltration subunit, and a purified CO2 collection subunit. Aspects of the invention include larger assemblages of multiple individual modular units that are engaged and may have one or many individual modular units that include a CO2 gas / liquid contactor subunit, a carbonate production subunit, an alkali enrichment subunit, a water softening subunit, a cation recovery subunit, a heat exchange subunit, a reverse osmosis subunit, a nanofiltration subunit, a microfiltration subunit, an ultrafiltration subunit, and a purified CO2 collection subunit. Also provided are methods of using the units / systems in CO2 sequestration protocols.

[0148] Direct Air Capture (DAC) with Repurposed Equipment

[0149] Embodiments of the disclosure include practicing DAC with repurposed equipment, as developed further below. As discussed below, such embodiments may or may not employ the particular CO2 capture approach described above. As such, embodiments described in this section may employ the CO2 capture approaches described above or other CO2 capture approaches.

[0150] Background

[0151] As reviewed above, concerns with increased levels of atmospheric carbon dioxide (CO2) inducing adverse climate changes have focused significant attention and resources on removing CO2 directly from earth’s atmosphere, a process known as Direct Air Capture (DAC). The concentration of CO2 in the atmosphere is approximately 410 parts per million (ppm) on a volumetric basis. Thus, capturing one tonne (1 tonne = 1 ,000 kg) of CO2 directly from the atmosphere requires processing at least 47 million cubic feet of air, more than the volume of the Reliant Astrodome (42 million cubic feet). The required processing volume will increase beyond 47 million cubic feet if the capture efficiency is less than 100% or if a significant fraction of the reduced-CC>2 exhaust gas exiting the capture system mixes with air feeding the system thereby diluting the inlet concentration.

[0152] One significant technical challenge is the need to avoid recirculation eddies where some portion of the exhaust air is recirculated to the system intake. In the case of a theoretical 1 MTA system, at a capture efficiency of 80%, the system would have to process the volume of the Reliant Astrodome (Houston, Texas) every 23 seconds! If some of the exhausted air, which would have a CO2 concentration of 82 ppm, recirculated in such a way as to mix with the inlet air to the capture system, the air would further dilute the inlet concentration. For example, if the inlet feed stream contained 20% of recirculated air from the purified air stream, the inlet concentration would drop from 410 ppm to 344 ppm and the capture facility would now have to process almost 20% more air to maintain the same CO2 capacity increasing both capital and operating expenses. To reduce these costs, the purified exhaust from the DAC facility must be discharged in such a way as to mitigate the possibilities of recirculation to the front of the process. To do this requires maintaining a significant distance between the system exhaust and the system inlet, so that recirculation eddies are minimized. To give a sense of the scale required for a 1 MTA system, moving the exhaust air one kilometer (1 km = 1 ,000 meters) away from the system intake with a minimal pressure drop of 12” of water column requires an air duct that is 70 feet in diameter. This will require significant capital investment.

[0153] In addition to the capital cost discussed above, moving such large quantities of ambient air through a capture system in such a way that the exiting air is not inadvertently recycled to the front of the system requires a significant amount of power. This is a second technical challenge. For example, capturing 1 million tonnes of CO2 per year (1 MTA) requires 200 MW of available, renewable power just to move the air volume through the system described above (Assuming a capture efficiency of 80% and a blower efficiency of 80%). This power is only the amount required to move the air through the capture system and away from the plant intake. This power does not include the additional power required for regenerating the capture media, compressing the recovered CO2to pipeline pressure for disposal or anything other power consuming system, all of which add to the power demand. For example, Carbon Engineering estimates that compression to bring purified CO2up to pipeline pressure of 151 bar requires an additional 22MW for their 1 MTA facility (Keith, D.W., Holmes, G., Angelo, D.S., and Heidel, K. (2018). Joule 2, 1573-1594).

[0154] A third technical challenge is the requirement that the power supplying a DAC facility should have a near-zero carbon footprint. Otherwise, the net capture rate (what is captured at the DAC facility less what is emitted at the power source) will be reduced due to the carbon footprint of the power facility supplying the energy (for example, if the power source were a natural gas combined cycle plant, the emissions of CO2 at the power plant would amount to 60% of the net captured CO2 of the DAC system just to move the exhaust air away from the intake). Not only should the power have a minimal carbon footprint, but it should also be available without interruption so that the DAC facility can operate continuously. The intermittency of renewable power is a known challenge, especially for wind-derived and solar-derived power. When renewable energy is not sufficient to supply the grid demand, the balance of power is supplied with non-renewable sources such as those from hydrocarbon-fired power plants. Such hydrocarbon fuels, notably coal, oil, and natural gas, produce CO2 which is typically released into the atmosphere when they are used for power generation.

[0155] Thus, there are several technical issues that need to be addressed before DAC can be realized on a large scale. These issues include the high capital cost associated with a DAC facility, overall power demand, the availability of renewable energy to power the capture process, and exhaust gas recirculation.

[0156] Repurposing Existing Equipment to Address above DAC Technical Issues

[0157] The inventors have realized that DAC technical issues, e.g., as described above, may be overcome by repurposing equipment, such as power plant equipment, for use as a facility for removal of CO2 directly from the ambient air. The repurposed equipment can be from idled power plants, power plants that operate intermittently, or newly constructed power plants that can serve both purposes. For example, an embodiment is the construction of a new Natural Gas Combined Cyble (NGCC) power plant that is able to be used for DAC when renewable power is available. Embodiments of the disclosure address a number of technical challenges associated with current versions of Direct Air Capture by minimizing overall equipment costs and addressing problems associated with the intermittency of renewable energy.

[0158] Embodiments of the disclosure provide configurations for Direct Air Capture (DAC) that repurpose existing equipment, such as air moving equipment or pollution control equipment, at a combustion-based power generating facility for the purposes of doing direct air capture of carbon dioxide. In some instances, embodiments of the invention use the equipment originally designed to move air through a combustion-based power plant to move ambient air through a system designed to remove carbon dioxide directly from the atmosphere, when the equipment is no longer producing electrical power.

[0159] Embodiments of the disclosure address a number of technical challenges associated with Direct Air Capture. One advantage of this type of repurposing provided by embodiments of the disclosure is that most power generating facilities already have existing equipment for moving atmospheric air from an intake system through some vertical distance (such as the height of a stack) and possibly a horizontal distance as well. The reuse of both the equipment for moving the air, such as a blower or compressor, and the plumbing through which the air is moved are both aspects of embodiments of the disclosure. A second advantage of repurposing this type of equipment is that the power plants can be configured to operate as DAC facilities when renewable power is available and normal power generating facilities when it is not. For example, one type of power facility is known as a “peaker” facility that only operates when power demand is very high. Peaker units can be brought online very quickly and are thus used to supply power only when demand is very high. When demand is very high, the grid typically has a higher carbon footprint, so that operating a DAC facility during times of high demand only causes the burning of more hydrocarbons to supply power to the grid. However, repurposing a peaker facility (or more generally any facility that is not in use when power demand is low) offers a chance to use existing equipment for direct air capture. A last technical challenge that can be addressed by embodiments of the disclosure is the construction of the capture facility itself. In other embodiments of this invention, other portions of the power plant, such as a flue gas stack or existing pollution control equipment, are repurposed for Direct Air Capture, further reducing capital costs.

[0160] More generally, the power plant equipment may be available for repurposing for a variety of reasons. For one, it may be an idled plant that once operated but no longer does or it may be an operating plant that generates power intermittently (say less than 8000 hours per year). In some instances, the equipment is from an operating plant that does not generate power in periods of available renewable energy. In those cases, the same equipment may be used to provide power through hydrocarbon combustion when renewable power is not available and can be used for DAC when renewable power is available.

[0161] As one example, consider the equipment typically installed as part of a Natural Gas Combined Cycle (NGCC) power plant. In normal operation, an NGCC facility combusts natural gas (the fuel) with ambient air to drive a gas turbine which generates electric power. The hot exhaust from the gas turbine is then used to generate steam that drives a second turbine also generating electric power. The gas turbine is designed so that incoming air is usually compressed before mixing with the natural gas in the combustion region. This allows for more efficient combustion of the natural gas and improved power output. The hot exhaust gas then flows through the turbine, generating power, before exiting into the Heat Recovery Steam Generator (HRSG), where steam is produced by cooling the exhaust gas. At the end of the HRSG, the gas typically enters a vertically oriented flue stack. The flue gas exits the process out of the top of the stack. For certain design reasons, NGCC plants frequently have different numbers of gas turbines and steam turbines, such as two gas turbines and one steam turbine or three gas turbines and one steam turbine. In those cases, the steam generated from multiple HRSGs feeds a common steam turbine.

[0162] There are a number of advantages of reusing NGCC equipment for DAG. One advantage in using equipment from such a plant is that the gas exhaust from the stack is already located a significant distance (both horizontally and vertically) from the turbine intake, thus minimizing the exhaust recirculation discussed above. Secondly, the equipment for moving the air through the system is already in place, lowering total capital costs. The compression equipment that will move the air through the DAC facility already exists. If the turbine shaft is rotated in the appropriate direction, atmospheric air will again be drawn into the unit. The power for this rotation can be supplied either by an external motor applied to the shaft (power generating turbines frequently have a means of rotating the turbine shaft when not in normal operation to prevent bowing of the shaft) or by operating the power generating portion of the unit in such a way that the generator operates as a motor. (That is by supplying power to the turbine rather than removing it). In either of these cases, the turbine shaft may be rotated using externally supplied (and ideally low carbon) power.

[0163] A third advantage of these embodiments of the disclosure is the potential to reuse existing pollution control equipment thereby lowering the overall capital cost. As an example, consider a NGCC plant with an existing carbon capture unit operating on the flue gas. Such a unit may be reused for CO2 capture directly from the atmosphere merely by moving ambient air through the capture unit rather than flue gas. If a CO2 capture unit is not present, a different existing piece of pollution control equipment, such as a baghouse, electrostatic precipitator, or fuel gas desulfurization (FGD) unit, such as a wet scrubber or dry scrubber, can be retrofit for CO2 capture. If the power plant is permanently idled, the idled pollution control equipment can be permanently converted to use for CO2 capture.

[0164] Another embodiment is to retrofit the existing flue gas stack, HRSG or other portion of the system with components dedicated to CO2capture. In one instance, the flue gas stack could be retrofit with components suitable for DAC. For example, the stack might be filled with structured packing suitable for use in a liquid scrubber, which uses a capture solvent to remove the CO2 from the gas moving through the packing. The original flue gas stack of the NGCC, being reused as the shell of a DAC absorber. If a HRSG is used, the capture process might involve components containing a solid-state absorption material placed within the existing HRSG structure. In that case, the heat exchange equipment formerly used to recover heat out of the turbine exhaust can be used to regenerate the absorption media by evolving the concentrated CO2 to a location other than the atmosphere. Use of the flue gas stack structure or the HRSG structure enables a significant reduction in the overall capital cost of the system as the existing equipment and much of the other infrastructure can be reused. In general, these various options can be combined as would be obvious to one skilled in the art.

[0165] A fourth advantage of these embodiments of the disclosure is potential heat integration of a power plant and a DAC facility. For example, if the local grid conditions are such that significant amounts of renewable electricity are available during the day when production from solar power is high and unavailable during the evening when solar production drops off, then it would be desirable to run a DAC capture facility during the day when the NGCC plant might be idled and then restart the NGCC plant in the evening as renewable power becomes unavailable. In this case, the same facility can be used as a power plant to supplement the grid when renewable power is unavailable and be used as a DAC facility when renewable power is available.

[0166] Similar types of equipment reuse can be implemented at other types of power plants besides an NGCC, such that the disclosure is not limited to repurposing of NGCC power plants. Such plants include, but are not limited to, natural gas boiler power plants and coal-fired power plants. In these plants, combustion air is typically supplied from a blower or fan rather than a compressor. Sometimes, these fans are present on both the inlet (forced draft) and outlet (induced draft) of the unit. In other cases, only one of these may be present. Similarly, these units typically have a stack which can be converted into an absorption unit to remove CO2 from the air passing through the system. Coal fired power plants, in particular, usually contain significant amounts of additional pollution control equipment which can be used for CO2 removal including baghouses, electrostatic precipitators, dry scrubbers, and wet scrubber. If an existing CO2 capture unit is currently installed at the facility, that unit can also be converted to one for direct air capture (DAC).

[0167] As indicated above, a variety of CO2 capture systems are contemplated as part of these embodiments of the disclosure. These systems include amine scrubbers with solvent regeneration, absorbing membranes, dry capture of CO2 using lime or other materials, and other CO2 capture systems, e.g., as are known in the art. In some instances, capture systems that do not require purifying the CO2 prior to its disposition, using (or other source of heat) to regenerate a solvent, or compressing captured CO2 prior to its disposition, may be employed.

[0168] One CO2 capture system that achieves these objectives is a system for CO2 mineralization described above. As reviewed above, CO2 mineralization is a particular form of carbon capture wherein the CO2 is converted into an aqueous carbonate ion and precipitated as a solid carbonate like calcium carbonate or magnesium carbonate. For example, CO2 can be combined with aqueous ammonia and calcium ions to form calcium carbonate. If the calcium ions were balanced with chloride ions, the overall reaction would then be:

[0169] CO2+ 2NH3 + H2O + CaCI2CaCO3+ 2NH4CI The CaCO3will precipitate out of the aqueous solution and the ammonia and calcium ions can be regenerated by contacting with solid materials containing calcium and alkalinity.

[0170] There are many significant advantages of employing such a CO2 capture system. With regard to this disclosure, a significant advantage is that the CO2 does not need to be purified or concentrated. That is, the CO2 can be captured and processed into its final, mineralized form without any intermediate purification steps. A second advantage to CO2 mineralization arises from the fact that CO2 mineralization does not require thermal regeneration of the capture solvent. In many DAC capture systems, the CO2 is captured onto a sorbent or into a solvent that must then be regenerated thermally to evolve the CO2 in a different part of the system. If the overall process is to remain carbon negative, then the thermal energy must also be supplied renewably, such as from renewable electricity, increasing overall renewable demand. This is especially problematic if the same capture system is to be deployed on a system that operates as both a power producing facility when renewable power is low and a DAC facility when it is high. The electrical load required to regenerate the solvent or sorbent when it is operating on the power plant is a significant portion of the overall power of the plant. A mineralization system does not require thermal regeneration. Thus, the overall renewable power demand is decreased when the system is operating as a direct air capture facility and there is minimal impact on the power consumption of the plant when the facility is operating as a power producer.

[0171] Repurposed Natural Gas Combined Cycle (NGCC) Power Plant As reviewed above, an example of a repurposed power plant is a NGCC power plant repurposed for DAC. FIG. 6A provides a schematic representation of a Natural Gas Combined Cycle (NGCC) power plant 600. As illustrated in FIG. 6A., the NGCC power plant 600 combusts natural gas (the fuel) with ambient air in a combustion region 620 to drive a gas turbine 630 which generates electric power 640. The hot exhaust from the gas turbine 630 is then used to generate steam that drives a second steam turbine 650 also generating electric power 640. The gas turbine is designed so that incoming air is compressed in a compressor 610 before mixing with the natural gas in the combustion region 620. This allows for more efficient combustion of the natural gas and improved power output. The hot exhaust gas then flows through the turbine 630, generating power 640, before exiting into the Heat Recovery Steam Generator (HRSG) 660, where steam is produced by cooling the exhaust gas. At the end of the HRSG 660, the gas typically enters a vertically oriented flue stack 670. The flue gas (exhaust, 680) exits the process out of the top of the stack.

[0172] FIG. 6B provides a schematic representation of the same NGCC power plant repurposed for Direct Air Capture (DAC) in accordance with an embodiment of the invention. As illustrated in FIG. 6B., motor 635 (optionally powered by green energy) actuates turbine 630 to draw air through the compressor 610 and HRSG 660 to the stack 670, which is fitted with a CO2 mineralization capture system 690, such as described above, such that the stack 670 functions as a CO2 absorber and releases CO2 depleted exhaust gas 695.

[0173] AGGREGATES

[0174] As summarized above, the methods and systems of the invention may be employed to produce carbonate coated seed structures, e.g., carbonate coated aggregates or, optionally without a seed structure, e.g., pure carbonate aggregates, rocks, etc., for use in concretes and other applications. The carbonate coated aggregates may be conventional or lightweight aggregates.

[0175] Aspects of the invention include CO2sequestering aggregate compositions. The CO2 sequestering aggregate compositions include aggregate particles having a core and a CO2 sequestering carbonate coating on at least a portion of a surface of the core. The CO2 sequestering carbonate coating is made up of a CO2 sequestering carbonate material, e.g., as described above. The CO2 sequestering carbonate material that is present in coatings of the coated particles of the subject aggregate compositions may vary. In some instances, the isotopic profile of the core of the aggregate differs from the carbonate coating of the aggregate, such that the aggregate has a carbonate coating with a first isotopic profile and a core with a second isotopic profile that is different from the first.

[0176] In some instances, the carbonate material is a highly reflective microcrystalline / amorphous carbonate material. The microcrystalline / amorphous materials present in coatings of the invention may be highly reflective. As the materials may be highly reflective, the coatings that include the same may have a high total surface reflectance (TSR) value. TSR may be determined using any convenient protocol, such as ASTM E1918 Standard Test Method for Measuring Solar Reflectance of Horizontal and Low-Sloped Surfaces in the Field (see also R. Levinson, H. Akbari, P. Berdahl, Measuring solar reflectance - Part II: review of practical methods, LBNL 2010). In some instances, the backsheets exhibit a TSR value ranging from Rg;0 = 0.0 to Rg;0,= 1 .0, such as Rg;0,= 0.25 to Rg;0,= 0.99, including Rg;0,= 0.40 to Rg;0,= 0.98, e.g., as measured using the protocol referenced above.

[0177] In some instances, the coatings that include the carbonate materials are highly reflective of near infrared (NIR) light, ranging in some instances from 10 to 99%, such as 50 to 99%. By NIR light is meant light having a wavelength ranging from 700 nanometers (nm) to 2.5 millimeters (mm). NIR reflectance may be determined using any convenient protocol, such as ASTM C1371 Standard Test Method for Determination of Emittance of Materials Near Room Temperature Using Portable Emissometers or ASTM G173 Standard Tables for Reference Solar Spectral Irradiances: Direct Normal and Hemispherical on 37° Tilted Surface. In some instances, the coatings exhibit a NIR reflectance value ranging from Rg;0 = 0.0 to Rg;0 = 1 .0, such as Rg;0 = 0.25 to Rg;0 = 0.99, including Rg;0 = 0.40 to Rg;0 = 0.98, e.g., as measured using the protocol referenced above.

[0178] In some instances, the carbonate coatings are highly reflective of ultraviolet (UV) light, ranging in some instances from 10 to 99%, such as 50 to 99%. By UV light is meant light having a wavelength ranging from 400 nm and 10 nm. UV reflectance may be determined using any convenient protocol, such as ASTM G173 referenced above. In some instances, the materials exhibit a UV value ranging from Rg;0 = 0.0 to Rg;0 = 1.0, such as Rg;0 = 0.25 to Rg;0 = 0.99, including Rg;0 = 0.4 to Rg;0 = 0.98, e.g., as measured using the protocol referenced above. In some instances, the coatings are reflective of visible light, e.g., where reflectivity of visible light may vary, ranging in some instances from 10 to 99%, such as 10 to 90%. By visible light is meant light having a wavelength ranging from 380 nm to 740 nm. Visible light reflectance properties may be determined using any convenient protocol, such as ASTM G173 referenced above. In some instances, the coatings exhibit a visible light reflectance value ranging from Rg;0 = 0.0 to Rg;0 = 1 .0, such as Rg;0 = 0.25 to Rg;0 = 0.99, including Rg;0 = 0.4 to Rg;0 = 0.98, e.g., as measured using the protocol referenced above.

[0179] The materials making up the carbonate components are, in some instances, amorphous or microcrystalline. Where the materials are microcrystalline, the crystal size, e.g., as determined using the Scherrer equation applied to the FWHM of X-ray diffraction pattern, is small, and in some instances is 1 ,000 microns (pm) or less in diameter, such as 100 microns or less in diameter, and including 10 microns or less in diameter. In some instances, the crystal size ranges in diameter from 1 ,000 pm to 0.001 pm, such as 10 to 0.001 pm, including 1 to 0.001 pm. In some instances, the crystal size is chosen in view of the wavelength(s) of light that are to be reflected. For example, where light in the visible spectrum is to be reflected, the crystal size range of the materials may be selected to be less than one-half the "to be reflected" range, so as to give rise to photonic band gap. For example, where the to be reflected wavelength range of light is 100 to 1 ,000 nm, the crystal size of the material may be selected to be 50 nm or less, such as ranging from 1 to 50 nm, e.g., 5 to 25 nm. In some embodiments, the materials produced by methods of the invention may include rod-shaped crystals and amorphous solids. The rod-shaped crystals may vary in structure, and in certain embodiments have length to diameter ratio ranging from 500 to 1 , such as 10 to 1. In certain embodiments, the length of the crystals ranges from 0.5 pm to 500 pm, such as from 5 pm to 100 pm. In yet other embodiments, substantially completely amorphous solids are produced.

[0180] The density, porosity, and permeability of the coating materials may vary according to the application. With respect to density, while the density of the material may vary, in some instances the density ranges from 5 g / cm3to 0.01 g / cm3, such as 3 g / cm3to 0.3 g / cm3and including 2.7 g / cm3to 0.4 g / cm3. With respect to porosity, as determined by Gas Surface Adsorption as determined by the BET method (Brown Emmett Teller (e.g., as described in S. Brunauer, P. H. Emmett and E. Teller, J. Am. Chem. Soc., 1938, 60, 309. doi:10.1021 / ja01269a023) the porosity may range in some instances from 100 m2 / g to 0.1 m2 / g, such as 60 m2 / g to 1 m2 / g and including 40 m2 / g to 1 .5 m2 / g. With respect to permeability, in some instances the permeability of the material may range from 0.1 to 100 darcies, such as 1 to 10 darcies, including 1 to 5 darcies (e.g., as determined using the protocol described in H. Darcy, Les Fontaines Publiques de la Ville de Dijon, Dalmont, Paris (1856)). Permeability may also be characterized by evaluating water absorption of the material. As determined by water absorption protocol, e.g., the water absorption of the material ranges, in some embodiments, from 0 to 25%, such as 1 to 15% and including from 2 to 9 %.

[0181] The hardness of the materials may also vary. In some instances, the materials exhibit a Mohs hardness of 3 or greater, such as 5 or greater, including 6 or greater, where the hardness ranges in some instances from 3 to 8, such as 4 to 7 and including 5 to 6 Mohs (e.g., as determined using the protocol described in American Federation of Mineralogical Societies. "Mohs Scale of Mineral Hardness"). Hardness may also be represented in terms of tensile strength, e.g., as determined using the protocol described in ASTM C1167. In some such instances, the material may exhibit a compressive strength of 100 to 3,000 N, such as 400 to 2,000 N, including 500 to 1 ,800 N.

[0182] In some embodiments, the carbonate material includes one or more contaminants predicted not to leach into the environment by one or more tests selected from the group consisting of Toxicity Characteristic Leaching Procedure (TCLP), Extraction Procedure Toxicity Test, Synthetic Precipitation Leaching Procedure, California Waste Extraction Test, Soluble Threshold Limit Concentration, American Society for Testing and Materials Extraction Test, and Multiple Extraction Procedure. Tests and combinations of tests may be chosen depending upon likely contaminants and storage conditions of the composition. For example, in some embodiments, the composition may include As, Cd, Cr, Hg, and Pb (or products thereof), each of which might be found in a waste gas stream of a CO2 emitter, such as in the flue gas of a coal- fired power plant. Since TCLP tests for As, Ba, Cd, Cr, Pb, Hg, Se, and Ag, TCLP may be an appropriate test for aggregates described herein. In some embodiments, a carbonate composition of the invention includes As, wherein the composition is predicted not to leach As into the environment. For example, a TCLP extract of the composition may provide less than 5.0 mg / L As indicating that the composition is not hazardous with respect to As. In some embodiments, a carbonate composition of the invention includes Cd, wherein the composition is predicted not to leach Cd into the environment. For example, a TCLP extract of the composition may provide less than 1 .0 mg / L Cd indicating that the composition is not hazardous with respect to Cd. In some embodiments, a carbonate composition of the invention includes Cr, wherein the composition is predicted not to leach Cr into the environment. For example, a TCLP extract of the composition may provide less than 5.0 mg / L Cr indicating that the composition is not hazardous with respect to Cr. In some embodiments, a carbonate composition of the invention includes Hg, wherein the composition is predicted not to leach Hg into the environment. For example, a TCLP extract of the composition may provide less than 0.2 mg / L Hg indicating that the composition is not hazardous with respect to Hg. In some embodiments, a carbonate composition of the invention includes Pb, wherein the composition is predicted not to leach Pb into the environment. For example, a TCLP extract of the composition may provide less than 5.0 mg / L Pb indicating that the composition is not hazardous with respect to Pb. In some embodiments, a carbonate composition and aggregate that includes of the same of the invention may be non-hazardous with respect to a combination of different contaminants in a given test. For example, the carbonate composition may be non-hazardous with respect to all metal contaminants in a given test. A TCLP extract of a composition, for instance, may be less than 5.0 mg / L in As, 100.0 mg / L in Ba, 1 .0 mg / L in Cd, 5.0 mg / mL in Cr, 5.0 mg / L in Pb, 0.2 mg / L in Hg, 1 .0 mg / L in Se, and 5.0 mg / L in Ag. Indeed, a majority if not all of the metals tested in a TCLP analysis on a composition of the invention may be below detection limits. In some embodiments, a carbonate composition of the invention may be non-hazardous with respect to all (e.g., inorganic, organic, etc.) contaminants in a given test. In some embodiments, a carbonate composition of the invention may be non-hazardous with respect to all contaminants in any combination of tests selected from the group consisting of Toxicity Characteristic Leaching Procedure, Extraction Procedure Toxicity Test, Synthetic Precipitation Leaching Procedure, California Waste Extraction Test, Soluble Threshold Limit Concentration, American Society for Testing and Materials Extraction Test, and Multiple Extraction Procedure. As such, carbonate compositions and aggregates including the same of the invention may effectively sequester CO2 (e.g., as carbonates, bicarbonates, or a combinations thereof) along with various chemical species (or co-products thereof) from waste gas streams, industrial waste sources of divalent cations, industrial waste sources of proton-removing agents, or combinations thereof that might be considered contaminants if released into the environment. Compositions of the invention incorporate environmental contaminants (e.g., metals and co-products of metals such as Hg, Ag, As, Ba, Be, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, Zn, or combinations thereof) in a non-leachable form. The aggregate compositions of the invention include particles having a core region and a CO2 sequestering carbonate coating on at least a portion of a surface of the core. The coating may cover 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, including 95% or more of the surface of the core. The thickness of the carbonate layer may vary, as desired. In some instances, the thickness may range from 0.1 pm to 10 mm, such as 1 pm to 1 ,000 pm, including 10 pm to 500 pm.

[0183] The core of the coated particles of the aggregate compositions described herein may vary widely. The core may be made up of any convenient aggregate material. Examples of suitable aggregate materials include, but are not limited to: natural mineral aggregate materials, e.g., carbonate rocks, sand (e.g., natural silica sand), sandstone, gravel, granite, diorite, gabbro, basalt, etc.; and synthetic aggregate materials, such as industrial byproduct aggregate materials, e.g., blast furnace slag, fly ash, municipal waste, and recycled concrete, etc. In some instances, the core comprises a material that is different from the carbonate coating such as a pellet made from any of the superfine materials referenced above.

[0184] In some embodiments, the method of producing carbonate aggregates comprises the methods detailed in United States Provisional Application Serial No. 62 / 795,986 filed on January 23, 2019; the disclosure of which applications is herein incorporated by reference and includes methods whereby the carbonate aggregates are produced optionally without a seed structure, e.g., pure carbonate aggregates.

[0185] In some instances, the aggregates are lightweight aggregates. In such instances, the core of the coated particles of the aggregate compositions described herein may vary widely, so long as when it is coated it provides for the desired lightweight aggregate composition. The core may be made up of any convenient material. Examples of suitable aggregate materials include, but are not limited to: conventional lightweight aggregate materials, e.g., naturally occurring lightweight aggregate materials, such as crushed volcanic rocks, e.g., pumice, scoria or tuff, and synthetic materials, such as thermally treated clays, shale, slate, diatomite, perlite, vermiculite, blast furnace slag, basic oxygen furnace slag, electric arc furnace slag and fly ash; as well as unconventional porous materials, e.g., crushed corals, synthetic materials like polymers and low density polymeric materials, recycled wastes such as wood, fibrous materials, cement kiln dust residual materials, demolished / recycled / returned concrete materials, recycled glass, various volcanic minerals, granite, silica bearing minerals, mine tailings and the like.

[0186] The physical properties of the coated particles of the aggregate compositions may vary. Aggregates of the invention have a density that may vary so long as the aggregate provides the desired properties for the use for which it will be employed, e.g., for the building material in which it is employed. In certain instances, the density of the aggregate particles ranges from 1.1 to 5 g / cm3, such as 1 .3 g / cm3to 3.15 g / cm3, and including 1 .8 g / cm3to 2.7 g / cm3. Other particle densities in embodiments of the invention, e.g., for lightweight aggregates, may range from 1 .1 to 2.2 g / cm3, e.g., 1 .2 to 2.0 g / cm3or 1 .4 to 1.8 g / cm3. In some embodiments the invention provides aggregates that range in bulk density (unit weight) from 35 lb / ft3to 200 lb / ft3, or 50 lb / ft3to 200 lb / ft3, or 75 lb / ft3to 175 lb / ft3, or 50 lb / ft3to 100 lb / ft3, or 75 lb / ft3to 125 lb / ft3, or 85 lb / ft3to 1 15 lb / ft3, or 100 lb / ft3to 200 lb / ft3, or 125 lb / ft3to 150 lb / ft3, or 140 lb / ft3to 160 lb / ft3, or 50 lb / ft3to 200 lb / ft3, or 35 lb / ft3to 200 lb / ft3. Some embodiments of the invention provide lightweight aggregate, e.g., aggregate that has a bulk density (unit weight) of 75 lb / ft3to 125 lb / ft3, such as 90 lb / ft3to 1 15 lb / ft3. In some instances, the lightweight aggregates have a weight ranging from 50 to 1 ,200 kg / m3, such as 80 to 1 1 kg / m3.

[0187] The hardness of the aggregate particles making up the aggregate compositions of the invention may also vary, and in certain instances the hardness, expressed on the Mohs scale, ranges from 1 .0 to 9, such as 1 to 7, including 1 to 6 or 1 to 5. In some embodiments, the Mohs hardness of aggregates of the invention ranges from 2-5, or 2- 4. In some embodiments, the Mohs hardness ranges from 2-6. Other hardness scales may also be used to characterize the aggregate, such as the Rockwell, Vickers, or Brinell scales, and equivalent values to those of the Mohs scale may be used to characterize the aggregates of the invention; e.g., a Vickers hardness rating of 250 corresponds to a Mohs rating of 3; conversions between the scales are known in the art.

[0188] The abrasion resistance of an aggregate may also be important, e.g., for use in a roadway surface, where aggregates of high abrasion resistance are useful to keep surfaces from polishing. Abrasion resistance is related to hardness but is not the same. Aggregates of the invention include aggregates that have an abrasion resistance similar to that of natural limestone, or aggregates that have an abrasion resistance superior to natural limestone, as well as aggregates having an abrasion resistance lower than natural limestone, as measured by art accepted methods, such as ASTM C131 . In some embodiments aggregates of the invention have an abrasion resistance of less than 50%, or less than 40%, or less than 35%, or less than 30%, or less than 25%, or less than 20%, or less than 15%, or less than 10%, when measured by ASTM C131 referenced above.

[0189] Aggregates of the invention may also have a porosity within particular ranges. As will be appreciated by those of skill in the art, in some cases a highly porous aggregate is desired, in others an aggregate of moderate porosity is desired, while in other cases aggregates of low porosity, or no porosity, are desired. Porosities of aggregates of some embodiments of the invention, as measured by water uptake after oven drying followed by full immersion for 60 minutes, expressed as % dry weight, can be in the range of 1 to 40%, such as 2 to 20%, or 2 to 15%, including 2 to 10% or even 3 to 9%.

[0190] The dimensions of the aggregate particles may vary. Aggregate compositions of the invention are particulate compositions that may in some embodiments be classified as fine or coarse. Fine aggregates according to embodiments of the invention are particulate compositions that almost entirely pass through a No. 4 sieve (ASTM C125 and ASTM C33). Fine aggregate compositions according to embodiments of the invention have an average particle size ranging from 10 pm to 4.75 mm, such as 50 pm to 3.0 mm and including 75 pm to 2.0 mm. Coarse aggregates of the invention are compositions that are predominantly retained on a No. 4 sieve (ASTM C125 and ASTM C33). Coarse aggregate compositions according to embodiments of the invention are compositions that have an average particle size ranging from 4.75 mm to 200 mm, such as 4.75 to 150 mm in and including 5 to 100 mm. As used herein, "aggregate" may also in some embodiments encompass larger sizes, such as 3 inches (in.) to 12 in. or even 3 in. to 24 in., or larger, such as 12 in. to 48 in., or larger than 48 in..

[0191] In some instances, aggregates as described herein find use as aggregates of internal curing concretes, where the aggregates allow for the release of water over time to fully and evenly hydrate the cementitious components of the concrete. Internal curing aggregate products of such embodiments may be used to improve performance of concrete by increasing autogenous curing and reducing chemical shrinkage, leading to reduced cracking of the concrete body through the slow and uniform release of water throughout the placed concrete. Aspects of these embodiments include the use of internal curing aggregate products as described above to increase the performance of concrete, its various forms and types. As described above, the internal curing aggregate products are composed of, either partially or wholly, sequestered anthropogenic carbon from point source CO2 emitters, such as DAC systems and power plants, refineries and cement plants. The carbon, coming from carbon dioxide gas, is sequestered by methods of carbon capture and mineralization such as those in: U.S. Application Serial Nos. 14 / 204,994 published as US-2014-0322803-A1 ; 14 / 214,129 published as US 2014- 0271440 A1 ; and 14 / 861 ,996 published as US 2016-0082387 A1 ; as well as U.S. Patent Nos. 9,707,513; 9,714,406 and 9,993,799; the disclosures of which are herein incorporated by reference. The captured CO2 results in synthetic limestone in the form of calcium or other divalent cationic carbonate solids composing part or all of the internal curing aggregate products for concrete. Aspects of the invention include use of a rock composed wholly or partially of aggregate for use in concrete, mortar, pavements or other building materials that contain CO2 stemming from DAC systems or the combustion of fossil fuels or other forms of fuels and other CO2 criteria pollutant sources. In some embodiments, aggregates, either fine or coarse, manufactured from methods of carbon capture and mineralization as described above are employed as internal curing aggregates for concrete and meat ASTM Standard Specification for Lightweight Aggregate for Internal Curing of Concrete C1761 , which provides guidelines to estimate the amount of lightweight aggregate required for internal curing per unit volume of concrete. Further details regarding the use of aggregates in internal curing concrete applications are provided in U.S. Provisional Application Serial No. 62 / 624,022 filed January 30, 2018, the disclosure of which is herein incorporated by reference.

[0192] CONCRETE DRY COMPOSITES

[0193] Also provided are concrete dry composites that, upon combination with a suitable setting liquid (such as described below), produce a settable composition that sets and hardens into a concrete or a mortar. Concrete dry composites as described herein include an amount of an aggregate, e.g., as described above, and a cement, such as a hydraulic cement. The term "hydraulic cement" is employed in its conventional sense to refer to a composition which sets and hardens after combining with water or a solution where the solvent is water, e.g., an admixture solution. Setting and hardening of the product produced by combination of the concrete dry composites of the invention with an aqueous liquid results from the production of hydrates that are formed from the cement upon reaction with water, where the hydrates are essentially insoluble in water.

[0194] Aggregates of the invention find use in place of conventional natural rock aggregates used in conventional concrete when combined with pure Portland cement. Other hydraulic cements of interest in certain embodiments are Portland cement blends. The phrase "Portland cement blend" includes a hydraulic cement composition that includes a Portland cement component and significant amount of a non-Portland cement component. As the cements of the invention are Portland cement blends, the cements include a Portland cement component. The Portland cement component may be any convenient Portland cement. As is known in the art, Portland cements are powder compositions produced by grinding Portland cement clinker (more than 90%), a limited amount of calcium sulfate which controls the set time, and up to 5% minor constituents (as allowed by various standards). When the exhaust gases used to provide carbon dioxide for the reaction contain SOx, then sufficient sulphate may be present as calcium sulfate in the precipitated material, either as a cement or aggregate to offset the need for additional calcium sulfate. As defined by the European Standard EN197.1 , "Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates (3CaO-SiO2 and 2CaO-SiO2), the remainder consisting of aluminium- and iron-containing clinker phases and other compounds. The ratio of CaO to SiOs shall not be less than 2.0. The magnesium content (MgO) shall not exceed 5.0% by mass." The concern about MgO is that later in the setting reaction, magnesium hydroxide (Mg(OH)2), brucite, may form, leading to the deformation and weakening and cracking of the cement. In the case of magnesium carbonate containing cements, brucite will not form as it may with MgO. In certain embodiments, the Portland cement constituent of the present invention is any Portland cement that satisfies ASTM C150 Standard Specification of Portland Cement. ASTM C150 covers eight types of Portland cement, Types l-VIII, each possessing different properties, and used specifically for those properties.

[0195] Also of interest as hydraulic cements are carbonate containing hydraulic cements. Such carbonate containing hydraulic cements, methods for their manufacture and use are described in U.S. Patent No. 7,735,274; the disclosure of which applications are herein incorporated by reference.

[0196] In certain embodiments, the hydraulic cement may be a blend of two or more different kinds of hydraulic cements, such as Portland cement and a carbonate containing hydraulic cement. In certain embodiments, the amount of a first cement, e.g., Portland cement in the blend ranges from 10 to 90% (w / w), such as 30 to 70% (w / w) and including 40 to 60% (w / w), e.g., a blend of 80% OPC and 20% carbonate hydraulic cement. In some instances, the concrete dry composite compositions, as well as concretes produced therefrom, have a CARBONSTAR® Rating (CSR) that is less than the CSR of the control composition that does not include an aggregate of the invention. The CSR is a value that characterizes the embodied carbon (in the form of CaCOs or other XmCOs) for any product, in comparison to how carbon intensive production of the product itself is (i.e., in terms of the production CO2). The CSR is a metric based on the embodied mass of or offset quantity of CO2in a unit of concrete. Of the three components in concrete - water, cement and aggregate - cement is by far the most significant contributor to CO2emissions, roughly 1 :1 by mass (1 ton cement produces roughly 1 ton CO2). So, if a cubic yard of concrete uses 600 lb cement, then its CSR is 600. A cubic yard of concrete according to embodiments of the present invention which include 600 lb cement and in which at least a portion of the aggregate is carbonate coated aggregate, e.g., as described above, will have a CSR that is less than 600, e.g., where the CSR may be 550 or less, such as 500 or less, including 400 or less, e.g., 250 or less, such as 100 or less, where in some instances the CSR may be a negative value, e.g., -100 or less, such as -500 or less including -1 ,000 or less, where in some instances the CSR of a cubic yard of concrete having 600 lbs cement may range from 500 to - 5,000, such as -100 to -4,000, including -500 to -3,000. To determine the CSR of a given cubic yard of concrete that includes carbonate coated aggregate of the invention, an initial value of CO2generated for the production of the cement component of the concrete cubic yard is determined. For example, where the yard includes 600 lbs of cement, the initial value of 600 is assigned to the yard. Next, the amount of carbonate coating in the yard is determined. Since the molecular weight of carbonate is 100 a.u., and 44% of carbonate is CO2, the amount of carbonate coating is present in the yard is then multiplied by 44% (0.44) and the resultant value subtracted from the initial value in order to obtain the CSR for the yard. For example, where a given yard of concrete mix is made up of 600 lb of cement, 300 lb of water, 1 ,429 lb of fine aggregate and 1 ,739 lb of coarse aggregate, the weight of a yard of concrete is 4,068 lb and the CSR is 600. If 10% of the total mass of aggregate in this mix is replaced by aggregate with a carbonate coating, e.g., as described above, the amount of carbonate present in the revised yard of concrete is 317 lbs. Multiplying this value by 44% yields 139. Subtracting this number from 600 provides a CSR of 461 . SETTABLE COMPOSITIONS

[0197] Settable compositions of the invention, such as concretes and mortars, are produced by combining a hydraulic cement with an amount of aggregate (fine for mortar, e.g., sand; coarse with or without fine for concrete) and an aqueous liquid, e.g., water, either at the same time or by pre-combining the cement with aggregate, and then combining the resultant dry components with water. The choice of coarse aggregate material for concrete mixes using cement compositions of the invention may have a minimum size of about 3 / 8 inch and can vary in size from that minimum up to one inch or larger, including in gradations between these limits. Finely divided aggregate is smaller than 3 / 8 inch in size and again may be graduated in much finer sizes down to 200-sieve size or so. Fine aggregates may be present in both mortars and concretes of the invention. The weight ratio of cement to aggregate in the dry components of the cement may vary, and in certain embodiments ranges from 1 :10 to 4:10, such as 2:10 to 5:10 and including from 55:100 to 70:100.

[0198] The liquid phase, e.g., aqueous fluid, with which the dry component is combined to produce the settable composition, e.g., concrete, may vary, from pure water to water that includes one or more solutes, additives, co-solvents, etc., as desired. The ratio of dry component to liquid phase that is combined in preparing the settable composition may vary, and in certain embodiments ranges from 2:10 to 7:10, such as 3:10 to 6:10 and including 4:10 to 6:10.

[0199] In certain embodiments, the cements may be employed with one or more admixtures. Admixtures are compositions added to concrete to provide it with desirable characteristics that are not obtainable with basic concrete mixtures or to modify properties of the concrete to make it more readily useable or more suitable for a particular purpose or for cost reduction. As is known in the art, an admixture is any material or composition, other than the hydraulic cement, aggregate and water, that is used as a component of the concrete or mortar to enhance some characteristic, or lower the cost, thereof. The amount of admixture that is employed may vary depending on the nature of the admixture. In certain embodiments the amounts of these components range from 0.1 to 50% w / w, such as 2 to 10% w / w.

[0200] Admixtures of interest include finely divided mineral admixtures such as cementitious materials; pozzolans; pozzolanic and cementitious materials; and nominally inert materials. Pozzolans include diatomaceous earth, opaline cherts, clays, shales, fly ash, silica fume, volcanic tuffs and pumicites are some of the known pozzolans. Certain ground granulated iron and steel slags and high calcium fly ashes possess both pozzolanic and cementitious properties. Nominally inert materials can also include finely divided raw quartz, dolomites, limestone, marble, granite, and others. Fly ash is defined in ASTM C618.

[0201] Other types of admixture of interest include plasticizers, accelerators, retarders, air-entrainers, foaming agents, water reducers, corrosion inhibitors, and pigments.

[0202] As such, admixtures of interest include, but are not limited to: set accelerators, set retarders, air-entraining agents, defoamers, alkali-reactivity reducers, bonding admixtures, dispersants, coloring admixtures, corrosion inhibitors, dampproofing admixtures, gas formers, permeability reducers, pumping aids, shrinkage compensation admixtures, fungicidal admixtures, germicidal admixtures, insecticidal admixtures, rheology modifying agents, finely divided mineral admixtures, pozzolans, aggregates, wetting agents, strength enhancing agents, water repellents, and any other concrete or mortar admixture or additive. Admixtures are well-known in the art and any suitable admixture of the above type or any other desired type may be used; see, e.g., U.S. Patent No. 7,735,274, incorporated herein by reference in its entirety.

[0203] In some instances, the settable composition is produced using an amount of a bicarbonate-rich product (BRP) admixture, which may be liquid or solid form, e.g., as described in U.S. Patent No. 9,714,406; the disclosure of which is herein incorporated by reference.

[0204] In certain embodiments, settable compositions of the invention include a cement employed with fibers, e.g., where one desires fiber-reinforced concrete. Fibers can be made of zirconia containing materials, steel, carbon, fiberglass, or synthetic materials, e.g., polypropylene, nylon, polyethylene, polyester, rayon, high-strength aramid, (i.e. Kevlar®), or mixtures thereof.

[0205] The components of the settable composition can be combined using any convenient protocol. Each material may be mixed at the time of work, or part of or all of the materials may be mixed in advance. Alternatively, some of the materials are mixed with water with or without admixtures, such as high-range water-reducing admixtures, and then the remaining materials may be mixed therewith. As a mixing apparatus, any conventional apparatus can be used. For example, Hobart mixer, slant cylinder mixer, Omni Mixer, Henschel mixer, V-type mixer, and Nauta mixer can be employed.

[0206] Following the combination of the components to produce a settable composition (e.g., concrete), the settable compositions are in some instances initially flowable compositions, and then set after a given period of time. The setting time may vary, and in certain embodiments ranges from 30 minutes to 48 hours, such as 30 minutes to 24 hours and including from 1 hour to 4 hours.

[0207] The strength of the set product may also vary. In certain embodiments, the strength of the set cement may range from 5 MPa to 70 MPa, such as 10 MPa to 50 MPa and including from 20 MPa to 40 MPa. In certain embodiments, set products produced from cements of the invention are extremely durable, e.g., as determined using the test method described in ASTM C1 157.

[0208] STRUCTURES

[0209] Aspects of the invention further include structures produced from the aggregates and settable compositions of the invention. As such, further embodiments include manmade structures that contain the aggregates of the invention and methods of their manufacture. Thus in some embodiments the invention provides a manmade structure that includes one or more aggregates as described herein. The manmade structure may be any structure in which an aggregate may be used, such as a building, dam, levee, roadway or any other manmade structure that incorporates an aggregate or rock. In some embodiments, the invention provides a manmade structure, e.g., a building, a dam, or a roadway, that includes an aggregate of the invention, where in some instances the aggregate may contain CO2 from a fossil fuel source, e.g., as described above. In some embodiments the invention provides a method of manufacturing a structure, comprising providing an aggregate of the invention.

[0210] ALBEDO ENHANCING APPLICATIONS

[0211] In some instances, the solid carbonate product may be employed in albedo enhancing applications. Albedo, i.e., reflection coefficient, refers to the diffuse reflectivity or reflecting power of a surface. It is defined as the ratio of reflected radiation from the surface to incident radiation upon it. Albedo is a dimensionless fraction, and may be expressed as a ratio or a percentage. Albedo is measured on a scale from zero for no reflecting power of a perfectly black surface, to 1 for perfect reflection of a white surface. While albedo depends on the frequency of the radiation, as used herein Albedo is given without reference to a particular wavelength and thus refers to an average across the spectrum of visible light, i.e., from about 380 to about 740 nm. As the methods of these embodiments are methods of enhancing albedo of a surface, the methods in some instances result in a magnitude of increase in albedo (as compared to a suitable control, e.g., the albedo of the same surface not subjected to methods of invention) that is .05 or greater, such as 0.1 or greater, e.g., 0.2 or greater, 0.3 or greater, 0.4 or greater, 0.5 or greater, 0.6 or greater, 0.7 or greater, 0.8 or greater, 0.9 or greater, including 0.95 or greater, including up to 1 .0. As such, aspects of the subject methods include increasing albedo of a surface to 0.1 or greater, such as 0.2 or greater, e.g., 0.3 or greater, 0.4 or greater, 0.5 or greater, 0.6 or greater, 0.7 or greater, 0.8 or greater, 0.9 or greater, 0.95 or greater, including 0.975 or greater and up to approximately 1 .0.

[0212] Aspects of the methods include associating with a surface of interest an amount of a highly reflective microcrystalline or amorphous material composition, e.g., as described above, effective to enhance the albedo of the surface by a desired amount, such as the amounts listed above. The material composition may be associated with the target surface using any convenient protocol. As such, the material composition may be associated with the target surface by incorporating the material into the material of the object having the surface to be modified. For example, where the target surface is the surface of a building material, such as a roof tile or concrete mixture, the material composition may be included in the composition of the material so as to be present on the target surface of the object. Alternatively, the material composition may be positioned on at least a portion of the target surface, e.g., by coating the target surface with the composition. Where the surface is coated with the material composition, the thickness of the resultant coating on the surface may vary, and in some instances may range from 0.1 mm to 25 mm, such as 2 mm to 20 mm and including 5 mm to 10 mm. Applications in use as highly reflective pigments in paints and other coatings like photovoltaic solar panels are also of interest.

[0213] The albedo of a variety of surfaces may be enhanced. Surfaces of interest include at least partially facing skyward surfaces of both man-made and naturally occurring objects. Man-made surfaces of interest include, but are not limited to: roads, sidewalks, buildings and components thereof, e.g., roofs and components thereof (roof shingles, roofing granules, etc.) and sides, runways, and other man-made structures, e.g., walls, dams, monuments, decorative objects, etc. Naturally occurring surfaces of interest include, but are not limited to: plant surfaces, e.g., as found in both forested and non-forested areas, non-vegetated locations, water, e.g., lake, ocean and sea surfaces, etc.

[0214] For example, the albedo of colored granules may be readily increased using methods as described herein to produce a carbonate layer on the surface of the colored roofing granules. While the thickness of the layer of carbonate material present on the surface of the colored roofing granules may vary, in some instances the thickness ranges from 0.1 to 200 pm, such as 1 to 150 gm, including 5 to 100 gm. A variety of different types of colored granules may be coated as described above, e.g., to enhance their reflectivity without substantially diminishing their color, if at all. Examples of types of granules that may be coated with a carbonate layer as described herein include roofing granules.

[0215] Roofing granules that may be coated with a carbonate layer, e.g., to improve their reflectivity without substantially reducing their color, if at all, may include a core formed by crushed and screened mineral materials, which are subsequently coated with one or more color coating layers comprising a binder in which is dispersed one or more coloring pigments, such as suitable metal oxides. Inorganic binders may be employed. The binder can be a soluble alkaline silicate that is subsequently insolubilized by heat or by chemical reaction, such as by reaction between an acidic material and the alkaline silicate, resulting in an insoluble colored coating on the mineral particles. The base particles employed in the process of preparing the roofing granules of the present invention can take several forms. The base particles may be inert core particles. The core particles may be chemically inert materials, such as inert mineral particles, solid or hollow glass or ceramic spheres, or foamed glass or ceramic particles. Suitable mineral particles can be produced by a series of quarrying, crushing, and screening operations, are generally intermediate between sand and gravel in size (that is, between about No. 8 and about No. 70 mesh). The core particles have an average particle size of from about 0.2 mm to about 3 mm, e.g., from about 0.4 mm to about 2.4 mm. In particular, suitably sized particles of naturally occurring materials such as talc, slag, granite, silica sand, greenstone, andesite, porphyry, marble, syenite, rhyolite, diabase, greystone, quartz, slate, trap rock, basalt, and marine shells can be used, as well as manufactured materials such as ceramic grog and proppants, and recycled manufactured materials such as crushed bricks, concrete, porcelain, fire clay, and the like. Solid and hollow glass spheres are available, for example, from Potters Industries Inc., P.O. Box 840, Valley Forge, Pa. 19482-0840, such as SPHERIGLASS® solid “A” glass spheres product grade 1922 having a mean size of 0.203 mm, product code 602578 having a mean size of 0.59 mm, BALLOTTINI impact beads product grade A with a size range of 600 to 850 micrometers (Nos. 20 to 30 mesh), and QCEL hollow spheres, product code 300 with a mean particle size of 0.090 mm. Glass spheres can be coated or treated with a suitable coupling agent if desired for better adhesion to the binder of the inner coating composition. In the granules, the particles can be coated with a coating composition that includes binder and a pigment. The coating binder can be an inorganic material, such as a metal-silicate binder, for example an alkali metal silicate, such as sodium silicate. The coatings pigments that may be used include, but are not limited to PC-9415 Yellow, PC-9416 Yellow, PC-9158 Autumn Gold, PC-9189 Bright Golden Yellow, V-9186 Iron- Free Chestnut Brown, V-780 Black, V0797 IR Black, V-9248 Blue, PC-9250 Bright Blue, PC-5686 Turquoise, V-13810 Red, V-12600 Camouflage Green, V12560 IR Green, V- 778 IR Black, and V-799 Black.

[0216] Methods as described herein may also be employed to produce frac sands. Frac sands are used in the oil and gas recovery industry to maintain porous void space in fractured geologic structure, so as to maintain geologic fracture integrity. Methods described herein may be employed to produce coated substrates and manufactured sands with tailorable surface coatings that can contribute to the buoyancy of the sand when in fluid flow. Methods as described herein may be employed to produce substrate with a closely regular patterning or irregular patterning of carbonate materials (crystalline or amorphous) as to effectively design the surface of the sands to maintain an above average buoyancy in the flow of fracking fluid, while the fluids are being pumped under very high pressure into the geologic fracture site. In some instances, the methods produce a product with a crystalline or amorphous however unreacted cementitious coating compound, such that upon contact with a second medium, the material could react as an expansive cement, providing void space for gas and fluid flow from surrounding geologic structure. This expansive property could be activated by intimate fluid or gas contact, sustained fluid contact, or other magnetic or sound wave activation provided from the geologic surface.

[0217] Methods of using the carbonate precipitate compounds described herein in varying applications as described above, including albedo enhancing applications, as well as compositions produced thereby, are further described in U.S. Patent No. 9,993,799 and in PCT published application No. WO / 2014 / 144 / 848; the disclosures of which applications are herein incorporated by reference. UTILITY

[0218] Systems and methods of the invention may be employed where it is desirable to capture CO2 from ambient air and reduce the amount of greenhouse gas in the atmosphere. In particular, systems and methods of the instant disclosure find use where it is desirable to improve, e.g., the amount of CO2captured by a system and the efficiency with which CO2 is captured. In addition, the invention may be employed to reduce the parasitic load of CO2 sequestration systems.

[0219] The subject solid, e.g., aggregate, compositions and settable compositions that include the same, find use in a variety of different applications, such as above ground stable CO2 sequestration products, as well as building or construction materials. Specific structures in which the settable compositions of the invention find use include, but are not limited to: pavements, architectural structures, e.g., buildings, foundations, motorways / roads, overpasses, bridges, parking structures, brick / block walls and footings for gates, fences and poles. Mortars of the invention find use in binding construction blocks, e.g., bricks, together and filling gaps between construction blocks. Mortars can also be used to fix existing structure, e.g., to replace sections where the original mortar has become compromised or eroded, among other uses.

[0220] Notwithstanding the appended claims, the disclosure is also defined by the following clauses:

[0221] 1 . A method of sequestering CO2 from ambient air, the method comprising directly contacting an aqueous capture liquid with the ambient air to produce a CO2 sequestering carbonate and CO2-depleted air to sequester the CO2 from the ambient air.

[0222] 2. The method according to Clause 1 , wherein the ambient air comprises an amount of CO2ranging from 300 ppm to 500 ppm.

[0223] 3. The method according to Clause 1 or 2, wherein the CO2-depleted air comprises an amount of CO2 ranging from 100 ppm to 300 ppm.

[0224] 4. The method according to any one of the preceding clauses, wherein the method does not include concentrating the CO2 from the ambient air prior to contacting it with the aqueous capture liquid.

[0225] 5. The method according to any one of the preceding clauses, wherein directly contacting the aqueous capture liquid with the ambient air comprises drawing in the ambient air from a surrounding environment using a gas conveyor, and contacting the ambient air with the capture liquid.

[0226] 6. The method according to Clause 5, wherein the gas conveyor is an air pump.

[0227] 7. The method according to Clause 5, wherein the gas conveyor comprises a turbine.

[0228] 8. The method according to any one of Clauses 5 to 7, wherein the gas conveyor is powered by a source of green energy.

[0229] 9. The method according to Clause 8, wherein the source of green energy is selected from wind energy, hydroelectric energy, solar energy, geothermal energy or nuclear energy.

[0230] 10. The method according to any of the preceding clauses, wherein the method comprises contacting the aqueous capture liquid with the ambient air in a countercurrent manner.

[0231] 11 . The method according to any one of Clauses 1 to 10, wherein the method comprises contacting the aqueous capture liquid with the ambient air in a co-current manner.

[0232] 12. The method according to any one of Clauses 1 to 10, wherein the method comprises contacting the aqueous capture liquid with the ambient air in a cross-current manner.

[0233] 13. The method according to any of the preceding clauses, further comprising gaseously cooling a source of waste heat.

[0234] 14. The method according to Clause 13, wherein the method comprises contacting the ambient air with the source of waste heat prior to the contact of the ambient air with the capture liquid.

[0235] 15. The method according to Clause 13, wherein the method comprises contacting the CC>2-depleted air with the source of waste heat.

[0236] 16. The method according to any one of Clauses 13 to 15, wherein the method comprises gaseously cooling the source of waste heat via a heating, ventilation, and air conditioning (HVAC) system of the source of waste heat.

[0237] 17. The method according to any one of Clauses 13 to 16, wherein the source of waste heat is a data center.

[0238] 18. The method according to any one of Clauses 7 to 17, further comprising:

[0239] (a) drawing in a CC>2-containing gas from a point source of gaseous CO2; and

[0240] (b) contacting the aqueous capture liquid with the CO2-containing gas. 19. The method according to Clause 18, wherein the C02-containing gas is a flue gas.

[0241] 20. The method according to Clause 18 or 19, wherein the method comprises combusting a fuel to drive the turbine, and thereby generating electricity and producing the CC>2-containing gas.

[0242] 21 . The method according to Clause 20, wherein the fuel is a natural gas.

[0243] 22. The method according to any one of Clauses 18 to 21 , wherein the point source of gaseous CO2 is comprised of a power plant.

[0244] 23. The method according to Clause 22, wherein the power plant is a combined cycle power plant.

[0245] 24. The method according to any one of Clauses 18 to 21 , wherein the point source of gaseous CO2 is comprised of an industrial plant.

[0246] 25. The method according to any one of Clauses 18 to 24, further comprising at least reducing the amount of ambient air being drawn in from the surrounding environment.

[0247] 26. The method according to any one of Clauses 18 to 25, further comprising:

[0248] (c) determining that the point source of gaseous CO2 is no longer emitting the CC>2-containing gas; and

[0249] (d) resuming or continuing the contact of the aqueous capture liquid with the ambient air.

[0250] 27. The method according to Clause 26, wherein the method comprises cyclically repeating steps (a)-(d).

[0251] 28. The method according to Clause 27, wherein the method comprises repeating steps (a)-(d) according to a cyclical availability of green energy.

[0252] 29. The method according to Clause 27 or 28, wherein the method comprises repeating steps (a)-(d) according to a day / night cycle.

[0253] 30. The method according to any one of the preceding clauses, wherein: the aqueous capture liquid comprises an aqueous capture ammonia; and producing the CO2 sequestering carbonate comprises generating an aqueous ammonium salt.

[0254] 31 . The method according to Clause 30, wherein the method further comprises regenerating aqueous capture ammonia from the aqueous ammonium salt.

[0255] 32. The method according to Clause 31 , wherein regenerating the aqueous capture ammonia from the aqueous ammonium salt comprises combining the aqueous ammonium salt with an alkalinity source. 33. The method according to Clause 32, wherein the alkalinity source is produced by dissolving a geomass.

[0256] 34. The method according to Clause 33, wherein the geomass comprises demolished, recycled or returned concrete.

[0257] 35. The method according to any one of Clauses 30 to 34, wherein the method comprises contacting the aqueous capture ammonia with the ambient air under conditions sufficient to produce an aqueous carbonate, and then contacting the aqueous carbonate with cations from a cation source to produce the CO2 sequestering carbonate.

[0258] 36. The method according to Clause 35, wherein regenerating the aqueous capture ammonia from the aqueous ammonium salt comprises distillation.

[0259] 37. The method according to any one of Clauses 30 to 34, wherein: the aqueous capture liquid comprises cations from a cation source; and the method comprises contacting the aqueous capture liquid with the ambient air under conditions sufficient to produce the CO2 sequestering carbonate.

[0260] 38. The method according to Clause 37, wherein the method does not comprise purification of the regenerated aqueous ammonia.

[0261] 39. The method according to any one of Clauses 35 to 38, wherein the cation source comprises an alkaline earth metal cation.

[0262] 40. The method according to Clause 39, wherein the cation source comprises Ca2+, Mg2+, or a combination thereof.

[0263] 41 . The method according to Clause 40, wherein the CO2 sequestering carbonate is comprised of calcium carbonate (CaCOs).

[0264] 42. The method according to any one of the preceding clauses, further comprising producing an aggregate from the CO2 sequestering carbonate.

[0265] 43. An aggregate produced according to the method of Clause 42.

[0266] 44. A concrete dry composite comprising: a cement; and an aggregate according to Clause 43.

[0267] 45. A settable composition produced by combining: an aggregate according to Clause 43; a cement; and a liquid.

[0268] 46. A system for sequestering CO2 from ambient air, the system comprising: a CO2 sequestration unit configured to directly contact an aqueous capture liquid with the ambient air and produce CO2-depleted air.

[0269] 47. The system according to Clause 46, wherein the CO2 sequestration unit is not configured to concentrate the CO2 from the ambient air prior to contacting it with the aqueous capture liquid.

[0270] 48. The system according to Clause 47, wherein the CO2sequestration unit is not configured to perform direct air capture (DAC).

[0271] 49. The system according to any one of Clauses 46 to 48, further comprising a gas conveyor configured to draw the ambient air into the CO2 sequestration unit from a surrounding environment and contact the ambient air with the capture liquid.

[0272] 50. The system according to Clause 49, wherein the gas conveyor is an air pump.

[0273] 51 . The system according to Clause 49, wherein the gas conveyor comprises a turbine.

[0274] 52. The system according to any one of Clauses 49 to 51 , wherein the gas conveyor is powered by a source of green energy.

[0275] 53. The system according to Clause 52, wherein the source of green energy is selected from wind energy, hydroelectric energy, solar energy, geothermal energy or nuclear energy.

[0276] 54. The system according to any one of Clauses 46 to 53, wherein the CO2 sequestration unit is configured to contact the aqueous capture liquid with the ambient air in a counter-current manner.

[0277] 55. The system according to any one of Clauses 46 to 53, wherein the CO2 sequestration unit is configured to contact the aqueous capture liquid with the ambient air in a co-current manner.

[0278] 56. The system according to any one of Clauses 46 to 53, wherein the CO2 sequestration unit is configured to contact the aqueous capture liquid with the ambient air in a cross-current manner.

[0279] 57. The system according to any one of Clauses 46 to 56, further comprising a source of waste heat gaseously connected to the CO2sequestration unit.

[0280] 58. The system according to Clause 57, wherein the CO2sequestration unit is gaseously connected to a heating, ventilation, and air conditioning (HVAC) system of the source of waste heat.

[0281] 59. The system according to Clause 57 or 58, wherein the source of waste heat is a data center. 60. The system according to any one of Clauses 51 to 59, wherein the CO2 sequestration unit is gaseously connected to a point source of gaseous CO2 configured to produce a C02-containing gas.

[0282] 61 . The system according to Clause 60, wherein the point source of gaseous CO2 comprises the turbine, and the turbine is configured for combustion of a fuel to generate electricity and produce the C02-containing gas.

[0283] 62. The system according to Clause 60 or 61 , wherein the point source of gaseous CO2 is comprised of a power plant.

[0284] 63. The system according to Clause 62, wherein the power plant is a combined cycle power plant.

[0285] 64. The system according to Clause 60 or 61 , wherein the point source of gaseous CO2is comprised of an industrial plant.

[0286] 65. The system according to any one of Clauses 60 to 64, further comprising a control unit operably connected to the point source of gaseous CO2, wherein the control unit is configured to cause:

[0287] (a) the gas conveyor to draw in the CO2-containing gas from the point source of gaseous CO2; and

[0288] (b) the CO2 sequestration unit to contact the C02-containing gas with the aqueous capture liquid.

[0289] 66. The system according to Clause 65, wherein the control unit is further configured to cause:

[0290] (c) the point source of gaseous C02to cease providing the C02-containing gas to the CO2sequestration unit; and

[0291] (d) the gas conveyor to resume or continue drawing in the ambient air.

[0292] 67. The system according to Clause 66, wherein the control unit is configured to activate and deactivate the point source of gaseous CO2.

[0293] 68. The system according to Clause 66 or 67, wherein the control unit is configured to cyclically repeat steps (a)-(d).

[0294] 69. The system according to Clause 68, wherein the control unit is configured to repeat steps (a)-(d) according to a cyclical availability of green energy.

[0295] 70. The system according to Clause 68 or 69, wherein the control unit is configured to repeat steps (a)-(d) according to a day / night cycle.

[0296] 71 . The system according to any one of Clauses 46 to 70, wherein the system is configured to: directly contact an aqueous capture liquid comprising an aqueous capture ammonia with the ambient air; produce a CO2 sequestering carbonate and an aqueous ammonium salt; and regenerate aqueous capture ammonia from the aqueous ammonium salt.

[0297] 72. The system according to Clause 71 , wherein the system is configured to regenerate the aqueous capture ammonia from the aqueous ammonium salt by contacting the aqueous ammonium salt with an alkalinity source.

[0298] 73. The system according to Clause 72, wherein the alkalinity source is produced by dissolving a geomass.

[0299] 74. The system according to Clause 73, wherein the geomass comprises demolished, recycled or returned concrete.

[0300] 75. The system according to any one of Clauses 71 to 74, further comprising a reformer configured to regenerate the aqueous capture ammonia from the aqueous ammonium salt.

[0301] 76. The system according to any one of Clauses 71 to 75, wherein the CO2 sequestration unit is configured to produce an aqueous ammonium carbonate by contacting the ambient air with the aqueous capture ammonia.

[0302] 77. The system according to Clause 76, further comprising a reactor configured to combine cations from a cation source and the aqueous ammonium carbonate to produce the CO2 sequestering carbonate and an aqueous ammonium salt.

[0303] 78. The system according to Clause 77, wherein the system is configured to regenerate the aqueous capture ammonia from the aqueous ammonium salt via distillation.

[0304] 79. The system according to Clause 77 or 78, wherein the reactor is operably connected to a cation source.

[0305] 80. The system according to any one of Clauses 71 to 75, wherein the CO2 sequestration unit is configured to produce a CO2 sequestering carbonate by contacting an aqueous ammonia capture liquid comprising cations from a cation source with the ambient air.

[0306] 81 . The system according to Clause 80, wherein the system is not configured to regenerate the aqueous capture ammonia via purification.

[0307] 82. The system according to any one of Clauses 77 to 81 , wherein the cation source comprises an alkaline earth metal cation. 83. The system according to Clause 82, wherein the cation source comprises Ca2+, Mg2+, or a combination thereof.

[0308] 84. A method of sequestering CO2 from ambient air, the method comprising removing CO2 from ambient air being conveyed through a power plant.

[0309] 85. The method according to Clause 84, wherein the power plant is operated intermittently.

[0310] 86. The method according to Clause 84, wherein the power plant is idled.

[0311] 87. The method according to any of the preceding clauses, wherein the power plant is a NGCC power plant.

[0312] 88. The method according to any of Clauses 84 to 87, wherein removing CO2 from ambient air being conveyed through a power plant comprises directly contacting an aqueous capture liquid with the ambient air.

[0313] 89. A system for sequestering CO2 from ambient air, the system comprising: a power plant configured to convey ambient air therethrough; and a CO2 sequestration unit configured to remove CO2 from ambient air being conveyed through a power plant.

[0314] 90. The system according to Clause 84, wherein the power plant is operated intermittently.

[0315] 91 . The system according to Clause 84, wherein the power plant is idled.

[0316] 92. The system according to any of Clauses 89 to 91 , wherein the power plant is a NGCC power plant.

[0317] 93. The system according to any of Clauses 89 to 92, wherein the CO2 sequestration unit directly contacts an aqueous capture liquid with the ambient air.

[0318] Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is readily apparent to those of ordinary skill in the art in light of the teachings of this invention that certain changes and modifications may be made thereto without departing from the spirit or scope of the appended claims.

[0319] Accordingly, the preceding merely illustrates the principles of the invention. It will be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples and conditional language recited herein are principally intended to aid the reader in understanding the principles of the invention and the concepts contributed by the inventors to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents and equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure. The scope of the present invention, therefore, is not intended to be limited to the exemplary embodiments shown and described herein. Rather, the scope and spirit of present invention is embodied by the appended claims.

Claims

WHAT IS CLAIMED IS:1 . A method of sequestering CO2 from ambient air, the method comprising directly contacting an aqueous capture liquid with the ambient air to produce a CO2 sequestering carbonate and CO2-depleted air to sequester the CO2 from the ambient air.

2. The method according to Claim 1 , wherein the method does not include concentrating the CO2 from the ambient air prior to contacting it with the aqueous capture liquid.

3. The method according to any one of the preceding claims, wherein directly contacting the aqueous capture liquid with the ambient air comprises drawing in the ambient air from a surrounding environment using a gas conveyor, and contacting the ambient air with the capture liquid.

4. The method according to any of the preceding claims, wherein the method comprises contacting the aqueous capture liquid with the ambient air in a counter-current manner.

5. The method according to any of the preceding claims, further comprising gaseously cooling a source of waste heat.

6. The method according to Claim 5, wherein the method comprises gaseously cooling the source of waste heat via a heating, ventilation, and air conditioning (HVAC) system of the source of waste heat.

7. The method according to Claim 5, wherein the source of waste heat is a data center.

8. The method according to any of the preceding claims, further comprising:(a) drawing in a CC -containing gas from a point source of gaseous CO2; and(b) contacting the aqueous capture liquid with the C02-containing gas.

9. The method according to Claim 8, wherein the CC -containing gas is a flue gas.

10. The method according to any one of Claims 8 to 9, wherein the point source of gaseous CO2 is comprised of a power plant.1 1 . The method according to Claim 10, wherein the power plant is a combined cycle power plant.

12. The method according to any one of Claims 8 to 11 , further comprising at least reducing the amount of ambient air being drawn in from the surrounding environment.

13. The method according to any one of Claims 8 to 12, further comprising:(c) determining that the point source of gaseous CO2 is no longer emitting the CC -containing gas; and(d) resuming or continuing the contact of the aqueous capture liquid with the ambient air.

14. The method according to any one of the preceding claims, wherein: the aqueous capture liquid comprises an aqueous capture ammonia; and producing the CO2 sequestering carbonate comprises generating an aqueous ammonium salt.

15. The method according to any one of the preceding claims, further comprising producing an aggregate from the CO2 sequestering carbonate.

16. An aggregate produced according to the method of Claim 15.

17. A concrete dry composite comprising: a cement; and an aggregate according to Claim 16.

18. A settable composition produced by combining: an aggregate according to Claim 16; a cement; and a liquid.

19. A system for sequestering CO2 from ambient air, the system comprising: a CO2 sequestration unit configured to directly contact an aqueous capture liquid with the ambient air and produce CO2-depleted air.

20. The system according to Claim 19, wherein the CO2 sequestration unit is not configured to concentrate the CO2 from the ambient air prior to contacting it with the aqueous capture liquid.

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