Carbon removal sand and methods and processes for its design, manufacture and use

Abstract

The present invention includes systems, methods, compositions, and processes for designing, manufacturing, and utilizing carbon dioxide sequestering substrates that can fully or partially replace natural sand in coastal engineering applications. These artificial substrates can offset the demand for scarce natural sand resources while also affecting the conversion of gaseous carbon dioxide to dissolved or solid state products, thereby offsetting the effects of anthropogenic climate change.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 256,986, filed October 18, 2021, U.S. Provisional Application No. 63 / 281,575, filed November 19, 2021, U.S. Provisional Application No. 63 / 298,412, filed January 11, 2022, U.S. Provisional Application No. 63 / 403,446, filed September 2, 2022, U.S. Provisional Application No. 63 / 377,171, filed September 26, 2022, and European Patent Application No. 22157366.0, filed February 17, 2022, which applications are incorporated by reference in their entireties herein. [Background technology]

[0002] Carbon dioxide is a potent greenhouse gas, currently comprising 0.0415% (415 ppm) of the Earth's atmosphere. Current anthropogenic emissions of carbon dioxide significantly exceed all available natural and man-made sinks, causing a sustained, long-term increase in the atmospheric concentration of carbon dioxide. Increasing atmospheric carbon dioxide concentrations have a variety of adverse effects on the natural environment, including increased global mean temperatures, rising sea levels, ocean acidification, and changes in annual weather patterns, collectively known as climate change. There is a need for systems, methods, compositions, and processes to achieve atmospheric carbon dioxide capture and sequestration.

[0003] In many coastal regions, climate change is manifested by increased rates of coastal erosion, sea level rise, increased frequency and magnitude of storm and flooding events, and nuisance flooding. Such impacts have increased demands for environmental management of water bodies (e.g., shelves, shorelines, marshes and other wetlands, lakes, rivers, estuaries, bays, etc.). Environmental management of water bodies can include beach nourishment, erosion control, storm protection, coastal protection, climate mitigation (including carbon removal), and other coastal engineering or coastal geological products or placement of coastal devices such as sand (all of which are collectively and generally referred to herein as "coastal construction projects"), most of which typically require large quantities of sand, gravel, and other compositions of natural materials to be mined or dredged from surrounding areas and placed in the coastal environment to act as a barrier or increase the sediment load in the system.

[0004] Materials and substrates used in coastal construction projects must meet stringent requirements for particle size, color, density, and fluid transport properties, among other characteristics. Naturally occurring deposits of suitable material are scarce in many coastal areas, where erosion and sea-level rise threaten to outstrip the ability to supply new material to coastal systems. Previous attempts have sought to alleviate the demand for natural sand in coastal construction by using non-natural materials, including, for example, recycled and crushed glass, but these materials have generally been found to have textures and properties that make them unsuitable substitutes for natural beach sand. Summary of the Invention

[0005] The present invention generally relates to systems, methods, compositions, and processes for designing, manufacturing, and utilizing carbon dioxide sequestering substrates that can fully or partially replace natural sand in coastal construction applications described herein while achieving atmospheric carbon dioxide capture and sequestration. FIG. 49 is a schematic representation of these systems, methods, and processes. Systems, methods, compositions, and processes as provided herein can meet one or more needs as described herein. For example, given the large volumes of sediment used in coastal construction projects, increasingly depleted on-site stockpiles of suitable materials, and the lack of suitable alternatives, it is desirable to have readily available engineered materials that can be tailored to fit the exact specifications of coastal construction, especially if such engineered materials can also remove excess carbon dioxide from the atmosphere and oceans, thereby addressing the root causes of increased coastal erosion levels, sea level rise, and increased frequency and magnitude of storm and flood events. Additionally, there is a need to identify the appropriate characteristics (grain size, color, density, hydraulic transport, etc.) of well-designed materials and develop methods and processes for the design, manufacture, utilization, or monitoring of engineered materials in actual coastal construction applications.

[0006] Naturally occurring geological minerals (e.g., olivine) and man-made industrial by-products (e.g., slags) can chemically interact with carbon dioxide, consuming protons and converting gaseous carbon dioxide into soluble dissolved bicarbonate and carbonate ions (HCO3 - and CO3 2- ) or solid-phase carbonate mineral species (CaCO 3(s) and MgCO 3(s) ), both of which serve to remove carbon dioxide from the atmosphere (a process known as "carbon dioxide sequestration"). Crushing these minerals into smaller particle sizes increases the available surface area of ​​such mineral particles, which may improve the rate at which they can sequester carbon dioxide from the atmosphere (a process known as "enhanced weathering").

[0007] To address the above needs, the present disclosure provides a novel engineered material ("carbon-removing sand") along with general methods and processes for: (1) optimizing the composition of the carbon-removing sand to control engineering properties such as carbon dioxide removal capacity, color, density, and hydraulic transport; (2) manufacturing and placing the carbon-removing sand mixture in coastal construction projects; and (3) monitoring the physical transport and chemical properties of the carbon-removing sand to verify the physical and chemical performance of the engineered material. The term "sand" in some contexts is used to refer to material with a particle size between 63 microns and 2000 microns (i.e., in the Wentworth classification), although the term "sand" as used herein as part of "carbon-removing sand" and "non-carbon-removing sand" also encompasses other sediments or particle sizes defined as gravel, silt, and mud (i.e., also in the Wentworth classification).

[0008] In one aspect, the present disclosure is directed to an engineered material, "carbon removal sand," and novel methods of selecting, preparing, mixing, transporting, distributing, and monitoring this material for use in coastal construction projects, including but not limited to those aimed at mitigating coastal erosion, climate change, and / or ocean acidification. Carbon removal sand may include specially selected, prepared, and mixed mineral particles that are suitable for use in coastal construction projects (e.g., to mitigate coastal erosion) and that interact with carbon dioxide (CO2) and / or dissolved carbonate [H2CO3] to convert bicarbonate [HCO3 - ], [CO3 2- ] ions, and / or solid-phase carbonate minerals [Ca,Mg]CO3, thus[3] simultaneously mitigating the effects of climate change, ocean acidification, and coastal erosion.

[0009] To be suitable for use in coastal construction projects, carbon-removal sand must meet various criteria regarding particle size distribution, fine and coarse particle content, elemental composition, color, density, and hydrodynamic transport properties. These requirements are necessary to (1) comply with applicable legal requirements, (2) meet applicable coastal construction project objectives regarding sediment matrix stability, erodibility, and transport, and (3) meet aesthetic and environmental protection standards regarding sand color and texture.

[0010] In another aspect, the present disclosure provides methods for controlling particle size distribution, fine and coarse particle content, elemental composition, color, density, and hydrodynamic properties of carbon removal sand to achieve required specifications for use in coastal construction projects. In some embodiments, these properties can be controlled by incorporating one or more sediment components as a mixed matrix, which can be optionally configured with different materials, mineralogy, particle size distribution, color, density, etc.

[0011] To efficiently remove carbon dioxide from the atmosphere, at least one component of the carbon removal sand can be made from an alkaline material. Examples include, but are not limited to, naturally occurring olivine, dunite, basalt, serpentine, brucite, wollastonite, or industrially produced mineral equivalents such as slag or mine tailings. These minerals interact with water, carbon dioxide, and / or carbonic acid to produce bicarbonate ions as a product, thereby reducing the acidity of the surrounding fluids, and converting the harmful carbon dioxide or carbonic acid to environmentally beneficial bicarbonate or carbonate ions or solid carbonate precipitates as a by-product. This reaction typically occurs on decadal to centennial timescales, sufficient for climate mitigation, and is essentially inert to the instantaneous environment. An example is provided below illustrating the interaction of forsterite (Mg2SiO4) with carbon dioxide (CO2) dissolved in seawater, but other minerals and rocks described in this disclosure may provide equivalent reactions that convert dissolved carbon dioxide and water (carbonic acid) to bicarbonate ions. (a) Mg2SiO4 + 4CO2 + 4H2O → 2Mg 2+ +4HCO3- +H4SiO4 (b) By converting carbon dioxide to dissolved bicarbonate and carbonate ions, this reaction serves to reduce the partial pressure of carbon dioxide in seawater. Coastal construction projects bring this seawater into intimate contact with the ocean surface and the atmosphere, resulting in a net transport of carbon dioxide across the air-ocean boundary, thereby resulting in a net sequestration of atmospheric carbon dioxide as bicarbonate and carbonate ions in seawater.

[0012] In some embodiments, the composition comprising the carbon removing component of carbon removing sand can further comprise one or more non-carbon removing components. These components include natural sand and sediment. Materials used include, but are not limited to, dredged soil, upland sand, silica sand (e.g., quartz and / or feldspar sand), carbonate sand, etc. The role of the materials may be to control the overall particle size distribution, fine and coarse particle content, elemental composition, color, density, and hydrodynamic properties of the final mix product to meet project specifications.

[0013] As discussed above, to simultaneously achieve the requirements of sand and sediment for coastal construction projects while maintaining the ability of the material to sequester carbon dioxide, in some embodiments of the invention, it may be necessary to specially prepare the carbon-removing mineral components and then mix these components with non-carbon-removing sands, such as native or exotic sands and sediments, in specially determined ratios to achieve the desired chemical, engineering, and aesthetic properties.

[0014] In yet another aspect, the process for preparing the carbon-depleted sand must be tailored so that the carbon-depleted sand and mixtures thereof achieve certain pre-determined properties specific to regional or local requirements.

[0015] In another aspect, the carbon removal material may be further modified by mixing with non-carbon removing sediments to achieve a combination of texture, color, and density with engineering properties suitable for use in coastal construction projects.

[0016] In another embodiment, the feedstock materials of the carbon removal material, and optionally the non-carbon removal material, may be crushed and / or ground (including via high pressure grinding rolls) to increase weatherable surface area, create microcracks for increased weathering, or achieve desired particle size requirements.

[0017] In another embodiment, the crushed and / or ground material may be size screened using methods including, but not limited to, sieving, gravity separation, or air classifiers to provide a final product having an average particle size and overall particle size distribution that meets the specifications of the applicable coastal construction project. The process is designed to capture fine material and / or coarse particles to produce a particle size material that matches the particle size distribution of the natural sediment at the site receiving the carbon removal sand or is suitable for the dual requirements of the coastal construction project and carbon dioxide removal.

[0018] In another embodiment, the carbon removing and / or non-carbon removing materials may be pre-sorted into various predetermined size ranges, and preferred sizes may be selected and / or mixed from these pre-sorted separates to achieve an overall mix suitable for use in a particular coastal construction project.

[0019] In another aspect of the invention, sediment transport models and geochemical reaction-transport models can be used in conjunction or in isolation to optimize the design of the carbon-removing sand mixture. This can include, but is not limited to, considering material composition, grain size, texture, porosity, permeability, crystal structure, density, mobility, environmental impact, and carbon dioxide removal potential. Any description of sediment transport models herein can also be applied to fluid dynamics models. The models described herein can incorporate the movement of fluids (e.g., water) and / or how carbon-removing and / or non-carbon-removing materials such as olivine and / or sand move within the fluid.

[0020] In one embodiment, the reaction-transport model and the sediment transport model can be used in combination or in isolation to optimize the carbon removal sand mix placement design for optimal carbon dioxide removal capacity, environmental impact, and coastal construction or other engineering outcomes, which may include, but is not limited to, considering the relative homogeneous or heterogeneous placement of the sand mix components.

[0021] In another aspect of the invention, the response-transport model and sediment transport model can be used in conjunction or in isolation to achieve optimal placement and location, including but not limited to considering river, estuary, lake, marsh, marsh, beach, shoreface, nearshore, or shelf locations.

[0022] As a result, this process has the potential side benefit of serving as a sediment transport and / or hydrodynamic tracer in coastal construction projects. For example, the color, albedo, chemistry, density, grain size, etc. of the carbon-removed sand components could be utilized as unique indicators of overall project sediment transport, project success, or other criteria.

[0023] In another aspect, to achieve mixing of the carbon removing and non-carbon removing components of the composition, the individual components can be pre-combined or, in another embodiment, transported or placed separately at the project site in a manner that achieves adequate mixing over the life of the project (i.e., mixing of the components occurs via conveyors, heavy machinery, bioturbation, and / or physical movement of sediment carried by waves, currents, and tides).

[0024] In another aspect, a sediment transport model can be used to determine how to mix the sediment components, including but not limited to, taking into account placement location along the coastal cross section or coastal longitudinal section, sediment properties, and how the sediment is distributed.

[0025] In another aspect, the carbon removal sand can be transported by land and sea to the placement site where it can be distributed using spreading equipment, either hydraulic or mechanical in nature, including techniques such as trucks, deck barges, dredges, hopper dredges, split hull barges, rainbows with modified dredging procedures, placement by direct offloading from dry bulk vessels, etc., as needed to achieve the placement design.

[0026] In another aspect, deployment can be performed at a single monolithic deployment site or at discontinuous segments that make up a project site.

[0027] In another aspect, the earth movement model can be used to guide deployment distribution logistics.

[0028] Another aspect of the invention relates to processes and methods for quantifying the rate and extent to which carbon-removed sands sequester carbon dioxide. These methods may include determining the concentration, flux, or isotopic composition of speciation resulting from dissolution of the carbon-removed sand. These methods may also include determining the effect of the carbon-removed sands on the ambient concentration, flux, or isotopic composition, and alkalinity of gaseous or dissolved carbon dioxide species found in the area surrounding the carbon-removed sands.

[0029] In another aspect, these methods may optionally include the introduction of chemical or isotopic tracers that help facilitate the determination of the rate or extent to which the carbon-depleted sand undergoes chemical dissolution or transformation.

[0030] In alternative embodiments, these methods can be performed at a single time point or as part of a time series.

[0031] In one embodiment, these determinations are made in the pore fluid in contact with the carbon removal sand and the water above it. In other embodiments, these determinations are made via the installation of chambers installed at the sediment surface that act to integrate the accumulation of reaction products and / or depletion of chemical reactants across the sediment-water interface.

[0032] In yet other embodiments, the methods may include determining the flux of dissolved or gaseous carbon dioxide in the overlying air or water by eddy covariance techniques.

[0033] In yet another embodiment, the methods can include determining the rate of dissolution or chemical alteration of the carbon-depleted sand material through quantification of the abundance of initial and subsequent mineral phases present in the sediment.

[0034] While all of the above methods can be carried out in situ, in yet other embodiments, any or all of the above methods can be carried out ex situ via construction of a reactor that serves to emulate the behavior of carbon removal sand in the environment. Such reactors can be carried out in a variety of sizes and scales, including, but not limited to, laboratory "bench-scale" reactors, batch-scale reactors, larger outdoor mesocosm-scale reactors, or other reactors designed to replicate desired real-world conditions in certain embodiments. Such reactors can optionally be constructed to be portable to facilitate transportation between locations.

[0035] In some embodiments of the present invention, the determination of the rate at which the carbon-removing sand undergoes reactions may be facilitated, predicted, or aggregated through the construction of a mathematical computer model. Such a model may accept certain environmental, biological parameters and / or physical properties of the carbon-removing sand, and / or the results of the aforementioned chemical or physical determinations, to output either the dissolution rate of the carbon-removing sand and / or the physical and chemical impacts that the carbon-removing sand has on the surrounding environment.

[0036] In some embodiments of the present invention, the determination of the rate at which the carbon removal sand removes carbon dioxide from the atmosphere over spatial and temporal scales can be facilitated, predicted, or aggregated through the construction of a mathematical computer model. Such a model can accept certain environmental parameters and / or physical properties of the carbon removal sand, the results of the aforementioned mathematical computer model, and / or the results of the aforementioned chemical or physical determinations, and output either the amount of atmospheric carbon capture from the carbon removal sand, and / or the physical and chemical impacts of the carbon removal sand on the surrounding environment, in each case over space and time.

[0037] Incorporation by Reference All publications, patents, and patent applications mentioned in this specification are incorporated by reference herein to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. To the extent that the publications and patents or patent applications incorporated by reference conflict with the disclosure contained herein, the specification is intended to supersede and / or take precedence over such conflicting material. [Brief description of the drawings]

[0038] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings (also referred to herein as "Figure" and "FIG.") in which:

[0039] [Figure 1] 1 illustrates a schematic of a long-term carbonate-silicate cycle, according to some embodiments. [Diagram 2] 1 illustrates a schematic of a chemical process by which olivine can be used for carbon dioxide capture and sequestration, according to some embodiments. [Diagram 3]1 illustrates a schematic of chemical reactions that enable carbon dioxide capture and sequestration using olivine, according to some embodiments. [Figure 4] 1A-1C are schematic diagrams illustrating olivine and a mixture of sand and olivine, according to some embodiments. [Diagram 5] 1 illustrates a schematic of one exemplary method for using carbon removal sand to remove atmospheric carbon dioxide and increase ocean alkalinity, according to some embodiments. [Figure 6] 1A-1C are schematic diagrams illustrating the use of wave energy to impact and fragment sand grains and / or carbon removal sand grains into small pieces, thereby facilitating dissolution of olivine, according to some embodiments. [Figure 7] 1 illustrates a schematic diagram of an example method for utilizing the ocean for natural carbon storage, according to some embodiments. [Figure 8] 1 illustrates a schematic diagram of an example bioreactor, according to some embodiments. [Figure 9] 1 illustrates a schematic diagram of an example of a system for deploying olivine for coastal beach nourishment, according to some embodiments. [Figure 10] 1 illustrates generally a computer system that may be programmed or configured to carry out the methods provided herein. [Figure 11] 1 illustrates a schematic of an exemplary reactor configured to take in seawater in which olivine and microbial biomass can be mixed to produce alkalinity. [Figure 12] 1 illustrates a schematic of an exemplary protocol for measuring, recording, and verifying (MRV) carbon removal, according to some embodiments. [Figure 13] 1 illustrates a schematic of the chemical reactions that occur during near-shore carbon capture when olivine is introduced to a target site, according to some embodiments. [Figure 14] 1 illustrates a schematic of the chemical reactions that occur during near-shore carbon capture when olivine is introduced to a target site, according to some embodiments. [Figure 15]1 illustrates a schematic of an environment in which olivine may be deployed for coastal carbon capture, according to some embodiments. [Figure 16] 1 illustrates a schematic of an environment in which olivine may be deployed for coastal carbon capture, according to some embodiments. [Figure 17] 1 illustrates a schematic of an environment in which olivine may be deployed for coastal carbon capture, according to some embodiments. [Figure 18] 1 illustrates a schematic of an environment in which olivine may be deployed for coastal carbon capture, according to some embodiments. [Figure 19] 1 illustrates a schematic of an environment in which olivine may be deployed for coastal carbon capture, according to some embodiments. [Figure 20] 1 illustrates a schematic of an environment in which olivine may be deployed for coastal carbon capture, according to some embodiments. [Figure 21] 13A-B are schematic diagrams illustrating plots of concentration of alkaline material in a flux chamber compared to a control location as a function of time, according to some embodiments. [Figure 22] 1 shows a schematic overview of a pore water method, according to some embodiments. [Diagram 23] 1 illustrates a schematic of a shrinking core model, according to some embodiments. [Figure 24] 1 illustrates a schematic diagram of dissolution rates of olivine having various grain sizes, according to some embodiments. [Diagram 25] 1 illustrates a schematic diagram of an exemplary modeling approach for particle distribution, according to some embodiments. [Figure 26] 13A-13C are schematic diagrams illustrating dissolution rates for different mixtures of olivine having different average grain sizes, according to some embodiments. [Figure 27] 1 illustrates a schematic of the effect of temperature and pH on the half-life of olivine, according to some embodiments. [Figure 28] 1 illustrates a schematic of examples of temporal and spatial factors that may vary for a coastal ecosystem, according to some embodiments. [Figure 29]13A-13C are schematic diagrams illustrating plots of temporal heterogeneity of various characteristics for a target location, according to some embodiments. [Diagram 30] 1 illustrates a schematic of examples of factors to consider when calculating alkalinity flux, according to some embodiments. [Diagram 31] 1 illustrates a schematic of examples of factors to consider when calculating alkalinity flux, according to some embodiments. [Diagram 32] 1 illustrates a schematic of examples of factors to consider when calculating alkalinity flux, according to some embodiments. [Diagram 33] 1 provides an overview of various approaches to measure, record, and verify carbon capture and olivine dissolution at different scales of cost and complexity, according to some embodiments. [Diagram 34] 1A-1D illustrate various reaction-transport modeling studies that can be used to simulate sediment pore water profiles, solid-phase chemistry, and benthic fluxes, according to some embodiments. [Diagram 35] 1A-1D illustrate various examples of sensors that can be used to measure, record, and verify carbon capture and / or olivine dissolution, according to some embodiments. [Diagram 36] 1A-1D illustrate various examples of sensors that can be used to measure, record, and verify carbon capture and / or olivine dissolution, according to some embodiments. [Figure 37] 1 illustrates a schematic of reactions that may occur when olivine sand is introduced to a beach, according to some embodiments. [Figure 38] 1 illustrates a schematic of reactions that may occur when olivine sand is introduced to a beach, according to some embodiments. [Figure 39] 1 illustrates a schematic of an approach to calculate CO2 sequestration from alkalinity flux based on a representation of how the DIC storage of water changes as a function of increasing alkalinity, according to some embodiments. [Diagram 40]1 shows a schematic diagram of a plot showing seawater age and subsurface depth in the Atlantic Ocean as a function of latitude (northern), according to some embodiments. [Diagram 41] FIG. 1 illustrates a schematic diagram of an exemplary coastal carbon capture life cycle analysis, according to some embodiments. [Diagram 42] 1 illustrates generally an example of a carbon payback time that can be achieved using the methods and systems disclosed herein, according to some embodiments. [Diagram 43] 1A-1C are schematic diagrams illustrating various plots showing exemplary olivine dissolution kinetics for olivine grains having different grain sizes, according to some embodiments. [Diagram 44] FIG. 1 is a schematic illustrating the effect of secondary carbonate precipitation on CO2 capture efficiency, according to some embodiments. [Diagram 45] 1 illustrates a schematic of the effect of secondary clay formation on carbon dioxide capture efficiency, according to some embodiments. [Diagram 46] 1A-1D illustrate schematic diagrams of beach nourishment, shore nourishment, and nearshore deployment of carbon capture sand, according to some embodiments. [Figure 47] 1A-1C are schematic diagrams illustrating carbon capture sand shelf and wetland configurations, according to some embodiments. [Figure 48] 1 illustrates a schematic diagram of a flow chart for measuring, recording, and verifying carbon credits associated with carbon removal sand activities, according to some embodiments. [Figure 49] 1 illustrates a schematic flow chart of one or more models integrated into the process of depositing carbon removal sand, according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] While various embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions may occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the present invention described herein may be employed.

[0041] Whenever the terms "at least," "greater than," or "greater than or equal to" appear before the first number of a series of two or more numbers, the terms "at least," "greater than," or "greater than or equal to" apply to each number in the series. For example, 1, 2, or 3 or more is equivalent to 1 or more, 2 or more, or 3 or more.

[0042] Whenever the terms "not greater than," "less than," or "less than or equal to" appear before the first number of a series of two or more numbers, the terms "not greater than," "less than," or "less than or equal to" apply to each number in the series. For example, 3, 2, 1 or less is equivalent to 3 or less, 2 or less, 1 or less.

[0043] The terms "real-time" or "real-time," as used interchangeably herein, generally refer to events (e.g., operations, processes, methods, techniques, calculations, computations, analyses, visualizations, optimizations, etc.) that are performed using recently obtained (e.g., collected or received) data. In some cases, real-time events may be performed nearly instantly or within a sufficiently short time span, such as within at least 0.0001 milliseconds (ms), 0.0005 ms, 0.001 ms, 0.005 ms, 0.01 ms, 0.05 ms, 0.1 ms, 0.5 ms, 1 ms, 5 ms, 0.01 seconds, 0.05 seconds, 0.1 seconds, 0.5 seconds, 1 second, or more. In some cases, a real-time event may execute nearly instantly or within a sufficiently short time span, such as within up to 1 second, within 0.5 seconds, within 0.1 seconds, within 0.05 seconds, within 0.01 seconds, within 5 ms, within 1 ms, within 0.5 ms, within 0.1 ms, within 0.05 ms, within 0.01 ms, within 0.005 ms, within 0.001 ms, within 0.0005 ms, within 0.0001 ms, or less.

[0044] overview To avoid the worst impacts of climate change, billions of tons of carbon dioxide must be rapidly removed from the atmosphere. There is an urgent need to identify carbon removal methods that are permanent, scalable, and economical. To combat climate change and mitigate its harmful effects in coastal environments, there is an urgent need for materials that can be used to physically protect and restore areas, combat rising carbon dioxide concentrations, and reduce the effects of ocean acidification. Moreover, these methods must be permanent, scalable, and economical.

[0045] Earth's long-term carbonate-silicate cycle is how Earth naturally captures carbon dioxide from the atmosphere. Over thousands of years, rain falling on exposed igneous rocks slowly dissolves such rocks in a process known as "weathering." Dissolved carbon dioxide in the rainwater reacts with the silicates in such rocks to produce alkalinity, shifting the equilibrium from carbonate to bicarbonate. This water eventually flows into the oceans, which eventually absorb carbon dioxide from the atmosphere as dissolved bicarbonate in seawater. Bicarbonates have a long residence time in the oceans, significantly longer than human timescales, and the subsequent precipitation of biotic or abiotic carbonate minerals by the increased bicarbonate leads to the formation of carbonate rocks.

[0046] "Ocean alkalinity enhancement" refers to a group of negative carbon dioxide emission (NET) technologies that aim to remove carbon dioxide from the atmosphere and store it over long timescales (tens of thousands to hundreds of thousands of years) by enhancing this natural weathering process.

[0047] One practical implementation of the theoretical "coastal weathering enhancement," "coastal carbon capture" (sometimes referred to under the trademark Coastal Carbon Capture(TM)), can be classified as a negative emission technology (NET) in the field of ocean alkalinity enhancement, which removes atmospheric carbon dioxide and stores it over long time scales (tens to hundreds of thousands of years) by seeding coastal systems with artificial carbon-stripping sand; such artificial materials can dissolve in seawater more quickly than under natural conditions, thereby enhancing the rate of carbon dioxide uptake by the oceans.

[0048] The long-term carbonate-silicate cycle is shown in Figure 1. Natural carbon dioxide removal by rock weathering can be achieved through the following steps:

[0049] 1. Rain falls on igneous rocks and slowly dissolves them.

[0050] 2. Carbonic acid dissolved in rainwater reacts with silicates in igneous rocks to produce alkalinity, shifting the equilibrium from carbonate to bicarbonate.

[0051] 3. This bicarbonate flows into the ocean.

[0052] 4. Bicarbonate combines with calcium and magnesium ions to form carbonate.

[0053] 5. Carbonates are deposited on the ocean floor, trapping carbon dioxide from the atmosphere into the rocks.

[0054] Figure 2 shows the chemical processes that occur as part of the long-term carbonate-silicate cycle involving mafic or ultramafic materials that result in carbon dioxide capture and sequestration, i.e., the conversion of dissolved carbon dioxide and water to bicarbonate via olivine, thereby enabling the uptake of atmospheric carbon dioxide into the surface ocean and an increase in seawater pH.

[0055] Figure 3 illustrates the chemical processes that allow for the capture and sequestration of carbon dioxide using olivine. When olivine dissolves, it produces magnesium ions (the second most abundant ion in the ocean after sodium), silicates (used by diatoms to build their skeletons), and dissolved carbon. With reference to Figures 2 and 3, when olivine dissolves in water, the reactions illustrated occur, which increase carbon dioxide uptake, increase the pH, and create alkalinity.

[0056] As a result, this process has the potential side benefit of countering ocean acidification, the process whereby increasing atmospheric carbon dioxide dissolves in seawater, lowering the pH (increasing acidity) (upper reaction in the diagram below). This reduces the ability of calcifying organisms like corals to grow and build exoskeletons or shells. As shown in Figures 2 and 3, dissolving alkaline substances (e.g., olivine) in water sequesters hydrogen ions into dissolved silicates (H4SiO4), molecules that can be utilized by diatoms, important photosynthetic algae that fix carbon dioxide and form the basis of the marine food web.

[0057] Unfortunately, natural chemical weathering is too slow to compensate for anthropogenic carbon dioxide emissions on time scales relevant to humans, and this natural process is already accounted for in the Earth's current carbon budget. The systems and methods disclosed herein can be deployed and implemented to enhance this natural process and further remove at least 1 gigaton of atmospheric carbon dioxide per year on a global scale.

[0058] How to remove carbon from the atmosphere Coastal carbon capture using carbon removal sand can be used to accelerate the Earth's natural carbon dioxide removal process. At current rates, the natural process of rock weathering by rainfall needs to be accelerated by at least 100 times to absorb the carbon dioxide emitted by human activities. Wave energy can enhance coastal carbon capture. Olivine-containing rocks can be placed in high-energy coastal environments where wave energy mechanically weathers the rocks. As sediment particles collide, this mechanical process accelerates the chemical dissolution of the material, at rates orders of magnitude faster than if the material were left to weather naturally where it was originally deposited.

[0059] In one aspect, the disclosure provides a method for designing and producing a carbon-removing sand mixture for spreading. The carbon-removing sand selection may be mafic, ultramafic, or indeed industrial by-product (see Table 1). As used herein, such materials are referred to as "alkaline materials" and may refer to one or more items in Table 1. This material may be mixed with non-carbon-removing sand materials (see Table 2), such as quartz, carbonates, dredged material, natural sediments, etc. to produce a mixture. An optimal particle size of the material is selected. In some cases, the selection may include the use of sediment transport models or equations, geochemical models, Regional Ocean Modeling Systems (ROMS), and / or Earth system models. In some cases, the selection may include the use of life cycle analysis. Such models may utilize one or more of the following parameters, but are not limited to: grid resolution, topography, sediment density, sediment size distribution, sediment composition, spatial variability of sediment properties including size and composition, distribution, vertical (number of layers, thickness) and horizontal, wave conditions, tides, currents, wind conditions, viscosity, diffusivity, roughness, mineralogy, chemical composition, pH, temperature, salinity, alkalinity, partial pressure of carbon dioxide (pCO2), dissolved inorganic carbon (DIC) content, dissolved organic carbon content, particulate organic carbon content, particulate inorganic carbon content, trace metal content, major cation and anion content, nutrient content, dissolved oxygen, redox, methane concentration, nitrous oxide concentration, irrigation, bioturbation, advection, diffusion, microbial community composition, carbon dioxide emissions, carbon dioxide equivalent emissions, energy, power, distance, cost, etc. In some cases, olivine may be the material of choice. Olivine is a silicate mineral found in ultramafic and mafic rocks. Olivine is extremely abundant and is found near the earth's surface throughout the world. Olivine rocks can be efficiently crushed down to grain sizes of silt, sand, and gravel.

[0060] In one aspect, the disclosure provides details regarding the extraction and grinding of carbon-removal sand and mixture components. Once carbon-removal sand is selected for application to a particular location, the constituent minerals of such carbon-removal sand are harvested (generally by quarrying rocks containing such minerals) and crushed or ground to an appropriate particle size for use at the target location of the applicable coastal engineering project. In some cases, non-carbon-removal sand components may be required and harvested (generally by quarrying rocks containing such minerals) and crushed or ground to an appropriate particle size for use at the target location of the applicable coastal construction project. In yet other instances, the non-carbon-removal sand components may consist of dredged material and may need to be harvested from the ocean bottom or other coastal, riverine or similar environments. In still other instances, the non-carbon-removal sand components may consist of naturally occurring sediments and may not require harvesting or processing.

[0061] To achieve a blend of carbon removal and non-carbon removal components, the individual components are pre-transported together, or in another embodiment, transported or placed separately at the project site in a manner that achieves adequate blending over the life of the project (i.e., blending of the components occurs via conveyors, heavy machinery, bioturbation, and / or physical movement of sediment driven by waves, tides, and currents). (c)

[0062] Coastal carbon capture using carbon removal sand may involve the following steps:

[0063] 1. Identifying a placement site, taking into account factors such as, but not limited to, climate, wave conditions, tides, currents, prevailing sediment transport mechanisms, land and sea accessibility, natural sediment size distribution and composition, local ecosystems, and social permits. In some cases, the process utilizes a sediment transport model that incorporates some or all of the above parameters as well as some or all of the following parameters: wave activity, tides, currents, wind, coastal sedimentology and composition, and weather. In yet other examples, the process utilizes a geochemical model that incorporates some or all of the following parameters: mineralogy, density, seawater chemistry, bioturbation, irrigation, and sediment composition. In yet other examples, the process utilizes a regional ocean model system and / or an Earth system model that incorporates some or all of the following parameters: ocean circulation, seawater residence time, marine biogeochemistry, seawater carbonate saturation state, wind speed, fetch, and atmospheric composition.

[0064] 2. Carbon Removal Sand Placement Design. Carbon removal sand can be designed to be placed underwater in the form of mounds, berms, shoreface nourishment, or similar features, underwater in a spread thin layer, on the beach as commonly used in beach nourishment, or in a thin layer arrangement in a bay, estuary, or marsh. Figures 46 and 47 show possible carbon removal sand placement options. Designs may consist of a monolithic placement covering a contiguous area, or several separate placement areas that are considered part of the same project design. Factors related to placement location and continuous or discontinuous placement include, but are not limited to, effects on sediment transport, effects on wave conditions, effects on erosion and deposition patterns of adjacent shorelines, and effects on carbon capture efficiency. Sediment transport models can be used to complete this task.

[0065] 3. Transport the selected material to a spreading location. The carbon removal sand can be transported (e.g., by rail, ship, truck) to the target location. The location can be a coastal or open ocean environment. The location can be an ocean, lake, or river. In some cases, the selection of the transportation mechanism and transportation route can include the use of a life cycle analysis that can utilize all or a portion of, but not limited to, the following parameters, among others, to calculate the carbon dioxide emissions associated with transporting the carbon removal sand.

[0066] 4. Spreading of the selected carbon-removing sand or carbon-removing sand mixture. The carbon-removing sand or carbon-removing sand mixture can be spread to the selected location from land or water (e.g., by truck, ship, or barge). In some embodiments, the sand can be placed from a split-hull barge, from shore via truck, or during dredging. In some embodiments, spreading can be accomplished entirely by mechanical means. In still other embodiments, spreading can leverage natural sediment movement or other natural forces to achieve spreading. In some cases, the selection of a spreading mechanism may include the use of sediment movement models and / or life cycle analysis, which may utilize all or some of the following parameters, including but not limited to: transportation distance, energy efficiency, power, cost, particle size, density, tonnage, wave energy, weather patterns.

[0067] 5. Environmental conditions promote carbon dioxide removal. This may include energy from waves, tides, and currents that act mechanically to accelerate the dissolution rate of the carbon-removing sand. Grain-grain collisions may form fine particles (<10 microns) that increase the surface area of ​​the olivine grains exposed to seawater, resulting in very rapid weathering. Grain-grain collisions may also prevent the formation of a surface coating on the carbon-removing sand. Bioturbation, waves, tides, and currents may also promote water recharge around the carbon-removing sand, thereby promoting fluid-mineral interactions and reducing or eliminating the formation of secondary mineral coatings and secondary weathering products (e.g., secondary clay and carbonate phase precipitation). In any case, the carbon-removing sand may result in rapid dissolution into water, promoting reactions that remove carbon dioxide from the ocean / atmosphere.

[0068] 6. Measurement, Reporting, and Verification (MRV) of Carbon Dioxide Removal. In some cases, measurements may be made to assess olivine dissolution rates and carbon dioxide removal. In some cases, these measurements may be chemical measurements including, but not limited to, carbonate chemistry, trace metals, nutrients, oxygen, organic carbon, salinity, and temperature of the water and / or pore water at and / or around the dispersal site. In some cases, geochemical models may be used to interpret the data for MRV purposes and / or to refine steps 1-6. In some cases, sediment transport models may be used to interpret the data for MRV purposes and / or to refine steps 1-6. In some cases, regional ocean system models and / or Earth system models may be used for MRV purposes. In some cases, multiple models may be coupled. Figure 48 illustrates a model configuration that may be employed to conduct MRV.

[0069] An example of an exemplary method for using olivine to remove atmospheric carbon dioxide and increase ocean alkalinity is shown in Figure 5. Wave energy can collide and break down sediment grains, promoting the dissolution of olivine, as shown in Figure 6.

[0070] The secondary benefits of the methods described herein include, for example, reducing the acidity of seawater. Ocean acidification has been shown to damage marine ecosystems. Carbon-removing sand can increase local pH levels and mitigate the adverse effects of ocean acidification on marine ecosystems, improving aquaculture and fisheries yields, not only repairing damage to marine ecosystems but also enhancing the local economy of the target placement site.

[0071] FIG. 7 shows one example of how the oceans can be used for natural carbon storage. Excessive carbon dioxide emissions can increase ocean acidity. The systems and methods of the present disclosure can be implemented to reduce seawater acidity and help the oceans safely store more carbon dioxide as bicarbonate.

[0072] Side benefits of the methods described herein may include, for example, supporting the growth of diatoms. Diatoms, marine photosynthetic microalgae, are key to the marine food web, capturing carbon dioxide through photosynthesis and producing 40% of the Earth's oxygen. Diatom populations have declined with increasing carbon dioxide levels, in part due to the damming of rivers, which has reduced silicate concentrations in the ocean and limited sediment movement. Some carbon-removing sands (e.g., olivine) are primarily composed of magnesium silicate, so increased silicate concentrations from dissolution of such carbon-removing sands can lead to diatom growth. Increased diatom populations would increase the health of marine ecosystems and support photosynthetic carbon capture.

[0073] Other side benefits may include, for example, assisting coastal communities facing accelerated coastal erosion and rising sea levels by providing a low-cost source of sediment (which in some cases may be paid for using carbon credits).

[0074] Mechanisms and interactions of weathering and dissolution Using energy from the natural environment, including but not limited to wave action, to crush the carbon-removal sand is crucial to the efficiency of carbon dioxide removal. Past analysis has shown that crushing the carbon-removal sand to a size smaller than 100 μm is very energy intensive. However, crushing the carbon-removal sand to a size larger than 300 μm requires much less energy. In some cases, the carbon-removal sand has a particle size of about 10 mm, 5 mm, 2 mm, 1 mm, 900 μm, 750 μm, 600 μm, 500 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, 50 μm, 25 μm or less. In some cases, the carbon-removed sand has a particle size of about 25 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 600 μm, 750 μm, 900 μm, 1 mm, 5 mm, 10 mm or more. In some cases, the carbon-removed sand has a particle size between the above two values, for example, between about 250 μm and about 500 μm. By utilizing the natural free energy of water movement to crush the carbon-removed sand, the crushing and grinding energy is further reduced to a small percentage of the total.

[0075] In some cases, grain-to-grain collisions may cause rapid fragmentation of the carbon removal sand. Grains of the carbon removal sand may be reduced in size by mechanical activation. In some cases, the movement of the water through which the carbon removal sand is fed may cause surface wear. In some cases, the surfaces of the carbon removal sand grains may be mechanically activated to enable and / or enhance carbon dioxide capture and deoxidation.

[0076] Dissolution kinetics FIG. 42 shows various plots illustrating exemplary olivine dissolution rates for olivine grains having different grain sizes. Dissolution times may decrease as the grain size of the carbon-removed sand decreases. The dissolution characteristics of the grains may be predicted or simulated using a shrink core model and one or more laws, equations, or principles governing the dissolution rates of the carbon-removed sand. In some cases, the shrink core model may be modified to allow for simulation of dissolution for realistic and commercially available grain size distributions of the carbon-removed sand. The models described herein may be generated by modifying an initial diagenesis model to incorporate dissolution kinetics of the carbon-removed sand corresponding to the shrink core model. The models may include and / or account for complete carbonate chemistry (e.g., DIC, ALK, pCO2, pH, carbonate precipitation / dissolution) as well as biogeochemical processes (including aerobic and anaerobic respiration, Fe / Mn oxide formation, pyrite, sulfide oxidation, etc.).

[0077] Secondary Minerals In some cases, secondary carbonate precipitation, as shown in FIG. 43, can affect the efficiency of carbon dioxide capture. Secondary carbonate precipitation can alter the reactions described herein such that for every mole of olivine introduced into the target environment, 2 moles of carbon dioxide are consumed and 0 moles of alkalinity are produced. This can result in a 50% decrease in carbon dioxide capture efficiency. The systems and methods disclosed herein can be implemented to minimize or reduce secondary carbonate precipitation. Carbonate precipitation rates can be strongly controlled by local variations in geochemistry and biogenic mineralization. In some cases, alkalinity transport can be the dominant process occurring in the sediment, and once mixed into the water column, alkalinity consumption can be low due to the long residence time of DIC and ALK in seawater.

[0078] In some cases, secondary clay formation, as shown in Figure 45, can affect carbon dioxide capture efficiency. Secondary clay formation can alter the reactions described herein such that for every mole of olivine, 8 / 3 moles of carbon dioxide are consumed and 8 / 3 moles of alkalinity are produced. This can result in a 33% reduction in carbon dioxide capture efficiency. The systems and methods disclosed herein can be implemented to minimize or reduce such secondary clay formation.

[0079] Although accelerated silicate weathering may be implemented in some cases, none of the prior studies have recognized or provided a method for producing engineered carbon-removal sand with the specific appropriate color, particle size, density, and reactivity required to meet the specific regulatory, environmental, cultural, aesthetic, and engineering requirements for coastal construction projects. Furthermore, the prior studies have completely ignored the engineering design of these specific attributes to create a safe and successful material for coastal construction projects. No material currently used in coastal construction projects provides additional public and ecological benefits through carbon dioxide capture, alkalinity generation, and seawater acidification mitigation. Similarly, none of the prior approaches have been able to simultaneously realize the benefits of producing carbon-removal sand suitable for coastal construction projects, namely coastal erosion mitigation, seawater acidification countermeasures, and atmospheric carbon dioxide reduction.

[0080] Design of placement materials Carbon removal sand The present disclosure provides carbon-removing sand, sand mixtures, and processes for producing the same. Carbon-removing sand is suitable for: [1] mitigating coastal erosion along coastlines; and [2] interacting with carbon dioxide (CO2) and / or dissolved carbonate [H2CO3] to convert bicarbonate [HCO3 - ], [CO3 2- ] ions, and / or solid-phase carbonate minerals [Ca, Mg]CO3, thus simultaneously mitigating the effects of climate change, seawater acidity, and coastal erosion.[3]

[0081] To be suitable for use in coastal construction, beach nourishment, and wetland restoration projects,[4] the produced carbon-removal sand and its blends should closely match or approximate the texture, particle size distribution, and color of natural sedimentary sands, comply with applicable legal requirements or standards, minimize or prevent environmental impacts, and, more generally, for aesthetic reasons. Thus, the processes for preparing the carbon-removal sand and sand blends can be tailored to produce and achieve these specific, pre-determined properties for the carbon-removal sand and its blends.

[0082] In one embodiment of the invention, to efficiently remove carbon dioxide from the atmosphere,[5] carbon removal sands can be produced from alkaline materials (typically naturally occurring olivine, dunite, basalt, serpentine, brucite, wollastonite, or industrially produced mineral equivalents such as slag). These minerals can interact with water, carbon dioxide, and / or carbonic acid to produce bicarbonate ions as a product, thereby reducing the acidity of the surrounding fluid and converting harmful carbon dioxide or carbonic acid to environmentally beneficial bicarbonate or carbonate ions. An example illustrating the reaction of forsterite (Mg2SiO4) is provided below, but other minerals and rocks described in this disclosure provide equivalent reactions to convert carbonic acid to bicarbonate ions. 1. CO2+H2O → H2CO3 2. Mg2SiO4+4H2CO3 → 2Mg 2+ +4HCO3 - +H4SiO4

[0083] Carbon removalThe dissolution of sand can affect the conversion of gaseous dissolved carbon dioxide to dissolved bicarbonate and carbonate ions, thereby increasing the capacity of freshwater and marine waters to store more carbon in solution. When present as dissolved bicarbonate and carbonate ions rather than carbon dioxide, these compounds no longer contribute to climate change and can act to counter the effects of ocean acidification.

[0084] In order to simultaneously achieve the sand and sediment requirements for coastal construction projects while maintaining the ability of such materials to remove carbon dioxide as described above,[7] it may be necessary to specially prepare reactive mineral components and then mix these components with native or exotic sands and sediments (i.e., sands that do not remove carbon dioxide) in specially determined ratios to achieve the desired chemical, engineering, and aesthetic properties. This process is described in detail below.

[0085] The process for preparing the carbon dioxide removal component of the carbon-removal sand begins with a source of alkaline material. A list of potential sources is shown in Table 1.

[0086] [Table 1]

[0087] Preparation of the carbon dioxide removal component of the carbon removal sand can proceed in two key stages.

[0088] (1) To increase the surface area of ​​the feedstock and provide new surfaces for interaction with carbon dioxide, the feedstock can be crushed and / or ground. Since the weathering process occurs only on the surface of the grains and in the microcracks created by the crushing / grinding process, it is essential to maximize the weathering of the feedstock by increasing the available reactive surface area to the greatest extent possible.

[0089] (2) The crushed and ground material can then be size-sorted using sieves, gravity separators, and air classifiers to provide a final product with an average particle size and overall particle size distribution that meets the engineering specifications of the coastal construction project. In some cases, the process can be designed to exclude excess fine and / or coarse material, producing intermediate particle size material that closely matches the particle size distribution of natural sediments in the geographic area receiving the carbon removal sand. Instead of preparing individual carbon dioxide removal component groups, it is also possible to pre-sort materials into various predetermined size ranges and select and / or blend from these pre-sorted isolates to achieve an overall mix suitable for use in a particular project.

[0090] In most or all cases, the carbon dioxide removal component may be further improved by blending it with non-carbon removal sand or sediment to achieve a combination of texture, color, density, and engineering properties suitable for use in coastal construction projects. A third step may be required to achieve this.

[0091] (3) The carbon dioxide removing mineral component can be mixed with one or more non-carbon removing sand or sediment materials to achieve a predetermined ratio that provides particular properties. A list of common non-carbon removing raw materials is provided in Table 2. Mixtures consisting of 1-50% carbon removing component will be most common, but other variations of the invention may use higher or lower percentages of carbon removing component.

[0092] [Table 2]

[0093] The purpose of blending the carbon removing and non-carbon removing components of the carbon removing sand is to achieve a final bulk product that meets various regulatory, aesthetic, and engineering requirements, including color, texture, particle size, density, cohesion, hardness, etc. To achieve the blend of carbon removing and non-carbon removing components of the carbon removing sand, the individual components will either be pre-transported together or, in another embodiment, transported or placed at the project site separately in a manner that will achieve the appropriate blend over the life of the project (i.e., blending of the components occurs via conveyors, heavy machinery, bioturbation, and / or physical movement of the sediment driven by waves, tides, and / or currents). Sediment transport models can be used to determine the appropriate method to obtain the final bulk product.

[0094] Improving the performance of carbon removal sand In another aspect, the present disclosure provides systems and methods for optimizing olivine for use in situ as carbon removal sand. Such optimization may include, for example, determining the optimal particle size distribution of olivine sand for use in carbon capture (including modeling the particle size distribution and placement design for a particular site, encompassing combinations of particle size, color, and mixture, which may use sediment transport models) and physically and / or chemically processing the olivine (e.g., using machinery) to prepare one or more carbon removal sand batches suitable for coastal engineering projects.

[0095] FIG. 4 illustrates olivine and a mixture of olivine and non-carbon-removing sand. In some cases, olivine may be mixed with natural beach sand before placing the olivine at the site of interest. The mixture including olivine may include at least about 5%, 10%, 15%, 20%, 25%, or 30% olivine by weight or volume. In some cases, the mixture may include more than 30% olivine by weight or volume. In some cases, the mixture may include less than 5% olivine by weight or volume. In some cases, the mixture may include from about 5% to about 30% olivine by weight or volume.

[0096] Olivine (or any other type of alkaline material) can be treated to produce particulates with increased surface area exposure and / or microfracture, thereby accelerating the dissolution and carbon dioxide capture process. The olivine dissolution and carbon dioxide capture process can also be accelerated by (i) using minerals that are easily weathered and soluble, (ii) increasing the amount of surface area of ​​the olivine particles exposed to the solvent (e.g., water or seawater), (iii) increasing fluid-mineral interaction, and / or (iv) reducing or eliminating the formation of secondary mineral coatings or secondary weathering products (e.g., precipitation of secondary clay and carbonate phases). The olivine dissolution and carbon dioxide capture process can be further accelerated by bioturbation, waves, tides, and / or currents that (1) disperse the olivine from the emplacement site, (2) cause grain-grain collisions, and (3) refresh and desaturate the overlying water.

[0097] Olivine is a common naturally occurring volcanic mineral with physical properties similar to quartz. Olivine may be 23% denser than pure quartz sand (1.43 tonnes / cy). Olivine sand is a clean upland sand that is about 25% denser than common silicate sands and can be artificially crushed to match natural grain sizes. Darker and lighter olivine sources are available to match the color of the native sand. One variety of olivine can be white olivine, or forsterite (Mg2SiO4). This is a magnesium-rich form of olivine known as forsterite (Mg2SiO4). Weathering one tonne of olivine can remove up to 1.25 tonnes of carbon dioxide from the atmosphere.

[0098] Manufacturing of placement materials In another aspect, the present disclosure provides systems and methods for preparing carbon-depleted sand for optimal dissolution. The carbon-depleted sand grains may be part of a feedstock material that includes olivine sand or a mixture that includes olivine sand and natural or exotic sands and sediments.

[0099] In some cases, the method may include grinding the carbon removal sand feedstock to obtain optimal particle size and agglomerating the raw or ground olivine into pellets. Such processing of the olivine may enhance dissolution of the olivine, thereby accelerating the carbon capture process. In some cases, the method may further include selecting, grinding, and / or producing suitable olivine sand and natural sediment for coastal construction, beach nourishment, and carbon capture purposes.

[0100] pellet In some embodiments, pelletized olivine aggregates formed from olivine fine particles can be prepared through a number of processes disclosed herein, including: [1] the use of binders (such as, but not limited to, clays, polysaccharides, proteinaceous compounds, resins, plastics, glass, etc.); [2] through encapsulation of small olivine particles with binders or other similar materials; or [3] through thermal fusion or physical compression of smaller olivine particles into larger aggregates.

[0101] In some embodiments, the pellets can be designed to either[4] remain substantially intact while maintaining improved surface area through internal porosity and permeability, or[5] degrade in a controlled manner to release olivine fine particles to the environment in a controlled manner over time. In some cases,[6] such pellets can be prepared such that dissolution of olivine occurs substantially faster than would occur with solid pure olivine particles of comparable size, thereby improving carbon capture processes while minimizing aesthetic, health, and ecological hazards and challenges posed by the use and utilization of olivine mineral fine particles.

[0102] Choosing a location The selection of locations to implement CCC may be crucial to the effectiveness of the method. Important factors may include climate, weather, wave conditions, tides, currents, ocean circulation patterns, sediment composition, sediment grain size, ecosystems, accessibility, and social license. In some cases, environmental assessments may be used to identify the presence or absence of threatened, endangered, protected, or culturally significant species, such as for nesting sites, and their respective sensitivity to sediment. In some cases, sediment transport models may be used to inform site selection and predict physical sediment behavior in a geographic region. In still other cases, reactive transport geochemical models may be used to simulate the distribution of carbon-removed sediments in target environments with one or more known biological, chemical, or ecological properties or characteristics. In still other cases, regional ocean model systems or Earth system models may be used to track air-sea-carbon dioxide gas fluxes and ensure sufficient time for air-sea carbon dioxide exchange and carbon removal. In some cases, sediment transport, reaction transport, and regional or Earth system models may be coupled, integrated, or iteratively used to inform site selection.

[0103] In some cases, measurements taken using sensors (remote, on-site, off-site) may be used to adjust where the carbon removal sand is introduced.

[0104] In some cases, geochemical models (e.g., reaction-transport) may be used to optimize where carbon removal sediments are introduced. Models can be configured to simulate sediment pore water profiles, water column and pore water chemistry (e.g., pCO2, DIC, pH, DO, TA, nutrients, metals, DOC), solid phase chemistry and benthic fluxes, secondary clay mineralogy, and trace metal speciation and cycling.

[0105] Location design The engineering design of the siting will be crucial to successfully achieving coastal construction goals, capturing carbon, and minimizing or eliminating environmental or cultural impacts.

[0106] In some cases, sediment movement models may be used to inform placement design, including placement volume, physical distribution of placement, sediment fractionation, placement location within the target area, and placement geometry.

[0107] In some cases, measurements obtained using sensors (remote, on-site, off-site) may be used to adjust the composition / form in which the carbon removal sand or mixture is placed.

[0108] In some cases, geochemical models (e.g., reaction-transport) may be used to optimize the configuration / morphology in which the carbon-removing or mixed sands are dispersed. Models can be configured to simulate sediment pore water profiles, water column and pore water chemistry (e.g., pCO2, DIC, pH, DO, TA, nutrients, metals, DOC), solid-phase chemistry and benthic fluxes, secondary clay mineralogy, trace metal speciation and cycling. In some cases, models can be used to simulate the distribution of carbon-removing sands in target environments with one or more known biological, chemical, or ecological properties or characteristics.

[0109] Sediment transport data and models may be linked with geochemical reaction-transport data and models to predict and / or constrain geochemical parameters, including but not limited to, carbon-removal sand dissolution, alkalinity production, trace metal dissolution, and nutrient availability, under different design scenarios. Sediment transport and reaction-transport models may be used together or separately to inform potential environmental impacts, such as the presence or absence of carbon-removal sand in ecologically or culturally significant areas, under different design scenarios and environmental conditions.

[0110] Shipping and Distribution [7] In another aspect, the disclosure provides systems and methods for shipping and placement of olivine. In some cases, the shipping and placement of olivine can be performed using an apparatus for distributing carbon removal sand in shallow marine environments. The apparatus can be, for example, a spreading apparatus for spreading olivine in a desired or optimal manner at a target location (e.g., a coast of interest).

[0111] In some cases, the methods of the present disclosure may include determining whether one or more dredging activities or other local modifications are necessary to optimally distribute the carbon removal sand. Such a determination may be made based on one or more sensor readings and / or information regarding the target locations where the carbon removal sand is to be distributed.

[0112] In some cases, the carbon removal sand may be treated prior to shipping to facilitate its shipping and distribution. For example, olivine may be modified to allow for the movement of ultra-fine material (e.g., to reduce liquefaction or capsize risk).

[0113] In some cases, measurements obtained using sensors (e.g., remote, on-site, off-site) can be used to adjust the rate at which carbon removal sand is introduced and the manner in which the carbon removal sand is distributed.

[0114] In some embodiments, various types and forms of marine emission reduction technologies may be implemented (e.g., shipboard olivine reactors powered by marine engines using ballast water). In some cases, direct placement technologies on bulk carriers and related improvements (e.g., open sea distribution for in-situ weathering) may be utilized. In some cases, grain washing and liquid alkaline systems may be used for turbidity reduction prior to placement.

[0115] In some cases, global logistics software may be used to mobilize idled offshore assets for carbon removal projects, including carbon removal sand.

[0116] FIG. 9 illustrates generally one example of a system that may be used to place carbon-removal sand in coastal engineering projects. The system may include, for example, a split hulled hopper barge. In some cases, rock containing carbon-removal minerals may be mined, crushed into carbon-removal sand components, and loaded onto dry bulk vessels for transport to a designated port. The carbon-removal sand components may then be loaded onto one or more split hulled hopper barges. In some embodiments, the barges are coupled together and towed to a designated placement location. Once the barge is placed at or near the designated placement location, the bottom of the barge may be configured to open in order to place the carbon-removal sand components at a specified rate to result in the on-site production of carbon-removal sand. In some cases, sediment movement modeling may be used to predict where and how the carbon-removal sand will move once placed, and in which direction it is likely to spread under different environmental conditions.

[0117] During conventional dredging operations, to reduce, avoid, or eliminate the emissions of carbon dioxide that occur during the combustion of fossil fuels, a predetermined percentage of carbon-removing sand can be mixed with the dredged sediment to: [1] obtain a net capture of a specified amount of carbon dioxide; and [2] ensure that the dredged sediment or other sediments meet engineering and regulatory requirements for disposal or beneficial reuse. Mixtures consisting of 1-50% carbon-removing sand component are most common, although other variations may use higher or lower amounts of the carbon-removing sand component.

[0118] To mix the carbon-removal sand with the dredged sediment, several different techniques can be used, depending on the type of dredging operation and the intended proportions of dredged sediment. Carbon-removal sand can be mixed directly with the dredged sediment by injecting it into the slurry pipeline during cutterhead dredging operations, pump-out hopper dredging, and other methods where dredged material is transported through a hydrologic slurry. When rear suction hopper dredges are used, the carbon-removal sand can be mixed in the sediment hopper or barge prior to discharge. Alternatively, the carbon-removal sand may be placed directly at the sediment destination in a specified amount and allowed to mix with the dredged sediment by bioturbation, wind, wave, tide, and current action.

[0119] Carbon Removal Marine Landfill Cap In another aspect, the disclosure provides a carbon-removing marine landfill cap, a manufacturing process thereof, and a process for quantifying carbon capture from the carbon-removing marine landfill cap. Marine landfills may serve as long-term ocean bottom depositories for unwanted construction debris, dredged material, and toxic pollutants. Currently, marine landfills are often "capped" with non-hazardous clay, sand, or other similar materials to prevent contamination of the overlying ocean waters and allow marine life to live in previously environmentally impaired areas. By using carbon-removing sand as the entirety or a component of the marine landfill cap, these landfills can serve as climate change mitigation sites and further promote the regeneration of environmentally impaired sites through the production of bicarbonate (alkalinity), which offsets ocean acidification and is beneficial to marine life.

[0120] The process of manufacturing and placing a carbon-removing marine landfill cap differs from a conventional marine landfill cap because 1) the depth (thickness) of the carbon-removing cap sand, 2) the particle size distribution of the carbon-removing cap sand, and 3) the possible mix of the carbon-removing cap and standard cap must be optimized to 1) prevent the release of toxic contaminants, etc., while ensuring that the carbon-removing cap sand is permeable enough to capture carbon over the long term, especially without saturating the pore waters, which would slow or stop the carbon-removal reaction. To achieve these objectives, the carbon-removing marine landfill cap may be placed in its entirety as a cap, applied as a single mix of carbon-removing cap and non-CO2 reactive cap sand, or applied to layers where the ratio of carbon-removing cap sand to non-CO2 reactive cap sand varies with depth, or where the particle size distribution of the carbon-removing cap and / or non-CO2 reactive cap varies with depth. In any situation, the carbon capture rate may vary with depth. In some cases, the carbon capture rate may be determined based on analytical and sensor measurements from specific locations fitted to a global model. In some embodiments, the appropriate deployment technique described above may be a function of local wave climate, ecology (bioturbation), ocean temperature, landfill material, and LCA (life cycle analysis), as the carbon dioxide released to deploy a carbon removal cap must be taken into account to ensure the cap is actually removing carbon.

[0121] Measurement, reporting and verification (MRV) [5] In another aspect, the present disclosure provides systems and methods for measurement, reporting, and verification (MRV) of carbon removal, as well as the ecological effects of carbon removal sand on carbon removal over a broad coastal region. Such measurement, reporting, and verification of carbon removal can be performed using one or more remote sensors, in-situ sensors, protocols for the use of such sensors (e.g., placement of sensors using benthic flux chambers), off-site (e.g., "bench-top" sensors and instruments), and algorithms for interpreting data obtained and derived from sensor readings. In some cases, sensor readings may include measurements of alkalinity, DIC, pCO2, pH, salinity, conductivity, dissolved oxygen, nutrients, trace metals, organic carbon, water temperature, wave activity, and / or additional chemical and physical properties. Systems and methods for MRV may also incorporate integration of sensor data with reaction-transport models, sediment transport models, regional ocean system models, Earth system models, or couplings of some or all of the aforementioned models. The presently disclosed systems may be used to demonstrate dissolution of carbon-removing sand and subsequent carbon dioxide capture based on dissolution of the carbon-removing sand. In some cases, the systems and methods disclosed herein may be implemented to predict movement and dissolution (e.g., by utilizing one or more models to simulate or predict dissolution of carbon-removing sand at a site of interest).

[0122] In a related aspect, the present disclosure provides systems and methods for simulating a site or environment of interest, which can enable the study of carbon-removed sand dissolution rates in a controlled environment intermediate between laboratory and field conditions. Such systems and methods may be implemented to determine and / or monitor the dissolution rate of carbon-removed sand, pore water or water column geochemistry, or benthic flux measurements, study the effect of temperature on carbon-removed sand dissolution and respiration, track effects on seawater pH and other water chemistry, monitor ecological responses and air-sea gas carbon dioxide fluxes, track trace metal fate, transport, and bioaccumulation, track the formation of secondary weathering products (e.g., chrysotile, carbonates, clays), and monitor the impact of the carbon dioxide sequestration process from carbon-removed sand on benthic invertebrates / biota.

[0123] In some embodiments, the MRV methods and protocols disclosed herein may be adapted or adjusted for different types of carbon-removing sand or different target locations of carbon-removing sand distribution. In such cases, the models used to predict or determine carbon-removing sand dissolution, reaction fluxes, and / or carbon sequestration may be adjusted based on the properties of the particular carbon-removing and non-carbon-removing sand mixtures used, the target location, and / or one or more sensor readings or measurements obtained at the site.

[0124] Models may be configured to simulate sediment pore water profiles, water column and pore water chemistry (e.g., pCO2, DIC, pH, DO, TA, nutrients, metals, DOC), solid phase chemistry and benthic fluxes, secondary clay mineralogy, and trace metal speciation and cycling.

[0125] In some cases, one or more sensors may be used to monitor and track decarbonized sand dissolution rates (pore water geochemistry, benthic flux measurements), carbon dioxide uptake, seawater deacidification, impacts on water chemistry, ecological responses, trace metal fate, transport, and bioaccumulation, and / or formation of secondary weathering products (e.g., chrysotile, carbonates, clays). In some cases, isotopic tracers may be used to track decarbonized sand dissolution and co-precipitation of secondary clay and carbonate phases. Sensors may also be used to track decarbonized sand particles over time (i.e., physical tracking of olivine with dyes / tracers, etc.).

[0126] In some cases, one or more sensors may be used to develop, calibrate, and / or validate sediment transport models and reaction transport models.

[0127] In some cases, reaction-transport models, sediment transport models, regional ocean model systems, and Earth system models may be used to simulate or predict dissolution rates of carbon-removal sediments, study the effects of temperature on olivine dissolution and respiration, track effects on seawater pH, track air-sea gas carbon dioxide fluxes, monitor and evaluate the fate and transport of trace metals, assess effects on benthic invertebrates / biota, track sediment properties (e.g., mineralogy, secondary carbonate / clay formation), monitor the effects of meteorology and hydrology (e.g., temperature, wind speed / direction, precipitation, salinity, turbidity, tides), or simulate physical sediment transport and / or redistribution of carbon-removal sediments.

[0128] In some cases, sediment transport models may be used to predict and quantify post-placement redistribution of carbon-removal sand in the coastal environment, benefits to coastal construction, effects on coastal processes pre-placement, and physical behavior including, but not limited to, physical weathering, vertical and horizontal sediment fractionation, turbidity, and wave conditions.

[0129] In some cases, sediment transport models, reaction-transport models, regional ocean system models, and Earth system models may be combined, integrated, or used iteratively to provide information on site selection, properties of ideal carbon removal sands and sand mixtures, deployment design, environmental impacts, effects on ocean acidification, alkalinity changes, nutrient availability, fate of trace metals, and atmospheric carbon dioxide removal. In some cases, models may be used to provide information on additional properties and effects associated with weathering.

[0130] The present disclosure also provides software configured to calculate carbon dioxide consumption and measure, record, and verify carbon removal. The software may be configured to determine carbon dioxide consumption and / or carbon removal based on one or more sensor readings, model outputs, and / or one or more input parameters. The one or more input parameters may relate to, for example, the physical or chemical properties of the carbon removal sand used, the ratio of carbon removal to non-carbon removal sand, the location where the carbon removal sand is distributed, the amount of carbon removal sand distributed to the target location, or the method / configuration by which the carbon removal sand is distributed (e.g., the method of distribution, the form of distribution, or the spatial characteristics of the distribution). In some cases, the sensor readings may include measurements of alkalinity, DIC, pCO2, pH, salinity, conductivity, dissolved oxygen, nutrients, trace metals, organic carbon, water temperature, wave activity, tidal currents, and / or additional chemical and physical properties.

[0131] In one embodiment, the disclosure provides methods and protocols for measuring, reporting, and verifying (MRV) carbon removal (e.g., by methods of coastal carbon capture using carbon removal sand). With reference to FIG. 12, the protocol may be submitted to an independent third party (e.g., academics, institutions, etc.) for verification. After verification, the protocol may be implemented by an individual or institution. Additional third parties may also ensure and verify compliance. An individual or institution implementing the MRV protocol may then submit a compliant methodology to a carbon credit verifier that is verified by a third party, and offsets or credits may be issued on a registry for sale in domestic and / or international markets.

[0132] In a further aspect, the present disclosure provides methods and processes for implementing coastal construction projects that are low-emission, carbon neutral, or carbon negative with respect to atmospheric greenhouse gas emissions. To accomplish this, the sediment used in coastal restoration projects may be mixed with one or more types of carbon removal sand, as described elsewhere herein, and a life cycle analysis must be performed on the project methods and processes.

[0133] Additionally, the present disclosure provides methods and processes for conducting low emission, carbon neutral, or carbon negative dredging operations. The methods and processes for conducting dredging operations may be either net neutral or net negative with respect to greenhouse gas emissions to the atmosphere. To accomplish this, the dredged material may be mixed with one or more types of carbon removal sand, as described elsewhere herein, and a life cycle analysis must be performed on the project methods and processes.

[0134] The methods and processes described herein may be applied to all types of construction activities, including land-based construction activities, all of which have the potential to be low-emission, carbon neutral, or carbon negative.

[0135] Whereas conventional dredging operations consume large amounts of fuel and correspondingly emit large amounts of greenhouse gases, the methods and processes described herein can enable dredging operations to be conducted in a carbon neutral or carbon negative manner over the life of the project. These methods and processes have significant advantages, allowing dredging operators to (i) mitigate carbon dioxide emissions on their own behalf or on behalf of their clients, (ii) avoid emissions caps and taxes, and (iii) operate in jurisdictions that impose voluntary or involuntary limitations on greenhouse gas emissions.

[0136] 13-14 and 36 show reactions that represent the chemical mechanisms by which nearshore carbon capture occurs when olivine is introduced to a site of interest as carbon removal sand (e.g., by adding olivine sand to a beach and mixing olivine sand with natural beach sand). While calculations may vary for other carbon removal sands, for every mole of olivine (which olivine may have or exhibit any of the physical or chemical properties or compositions described herein), four moles of carbon dioxide are consumed or captured, and four moles of alkaline material (bicarbonate or HCO3 - ) may be generated.

[0137] 15-20 show an environment including a first layer including seawater and a second layer including sediment and pore water. The sediment and pore water may span dimensions of about 10 centimeters (cm) or about 4 inches (in). The reactions shown and described in connection with FIGS. 13-14 and 36 may facilitate the capture of carbon dioxide (e.g., atmospheric or seawater carbon dioxide) and the release of magnesium, bicarbonate, and silicic acid. The overall reaction rate may be determined based on the speciation fluxes associated with the capture of carbon dioxide and the dissolution of alkaline materials.

[0138] FIG. 21 shows an overview of the pore water method for determining the flux of alkaline substances produced. The pore water method may be based on Fick's first law of diffusion. The flux of alkaline substances may be determined based on the diffusion coefficient (representing area per unit time) and the dC / dZ value (representing the change in concentration or amount of substance per unit volume as a function of position or dimensional length). If olivine is present in the pore water, a larger flux may be observed (steeper gradient and larger flux), whereas if olivine is not present, a smaller flux may be observed (shallower gradient and smaller flux).

[0139] Figure 22 shows the contracted core model including the deformed and undeformed volumes of an example olivine grain. The contracted core model is expressed as X=1-[1-R / (ρ×d)×t] 3 where X is the fraction of olivine that reacts, R is a function of pH and temperature, ρ is the molar density, d is the starting diameter, and t is time. One assumption of this model is that the particles are perfect spheres.

[0140] FIG. 23 shows the dissolution rates of olivine with various grain sizes. The percentage of olivine weathered over time can increase more rapidly for smaller grain sizes. For example, for olivine with a grain size of 30 microns, 10% of the olivine can weather within 3 years, 50% within 18 years, and 90% within 47 years. On the other hand, for olivine with a grain size of 64 microns, 10% of the olivine can weather within 6 years, 50% within 39 years, and 90% within 101 years. The rates shown here are static dissolution rates, which are generally based on inorganic chemical processes and may not include accelerated weathering due to wave energy and biological processes.

[0141] 24 shows an exemplary modeling approach for particle distribution. In one step, the modeling approach may include simulating particles to fit a desired particle size distribution. The modeling approach may further include shrinking each particle over a period of time (e.g., to simulate dissolution or erosion of one or more portions or layers of each particle) to determine the percentage of mass remaining as a function of time, and then summing the total mass of the particle and / or the total amount dissolved or eroded at various times.

[0142] Figure 25 shows the dissolution rates of different mixtures of olivine with different average grain sizes. In general, mixtures of olivine with smaller average grain sizes are likely to have shorter half-lives (i.e., it takes less time for half of the olivine composition to dissolve under certain conditions).

[0143] FIG. 26 illustrates the effect of temperature and pH on half-life. In some cases, the half-life of olivine dissolution may decrease as temperature increases. In some cases, the half-life of olivine dissolution may increase as pH increases. In some embodiments, the systems and methods disclosed herein may be implemented to optimize the temperature and pH of the olivine dissolution environment to decrease the half-life of olivine dissolution. In other embodiments, the systems and methods disclosed herein may be implemented to identify candidate locations having optimal temperatures and pH for the olivine dissolution environment to decrease the half-life of olivine dissolution.

[0144] The systems and methods disclosed herein may be configured or implemented to overcome challenges related to spatial and temporal heterogeneity, low signal-to-noise ratios of key parameters of MRV due to slow dissolution of olivine, and variability in the production of secondary mineral products. The systems and methods disclosed herein may also help overcome challenges in validation, such as, for example, objective criteria for the acceptance and validation of carbon credit sales, and ways to influence such criteria to accommodate coastal weathering processes.

[0145] The present disclosure provides methods for performing MRV (i.e., measurement, reporting, and verification) of carbon capture and / or olivine dissolution. In some cases, the method may include establishing a treatment location and a reference or benchmark location. The method may further include measuring alkalinity flux and / or other parameters at a network of discrete locations. In some cases, this may be repeated over time as olivine dissolves. The method may further include interpolating across time and space to determine an overall carbon removal and / or dissolution rate across an area or volume of the location. In some cases, the overall carbon removal and / or dissolution rate across the location may be determined in part using a numerical response-transport model that fits the measured data. In some cases, the carbon removal and / or dissolution rate across the location may be determined in part using a sediment transport model that indicates the location and concentration of carbon-removing sediment through time and space.

[0146] Figure 27 shows examples of temporal and spatial factors that may vary in coastal ecosystems, many of which are highly dynamic. Temporal factors may include, for example, diurnal factors (i.e., day-night variation), tides, seasonality, temperature, weather, and / or waves. Spatial factors may include, for example, location and hydrodynamics, water depth, tides, sediment type, grain size, sediment organic carbon content, and / or seafloor cover (e.g., seagrass, rocks, corals, etc.).

[0147] In some cases, the methods disclosed herein may include evaluating or assessing temporal heterogeneity, for example, by measuring water depth, temperature, salinity, pH, turbidity, chlorophyll concentration, and / or dissolved oxygen concentration over time. Figure 28 shows plots of temporal heterogeneity of various properties of a target site, including water depth, salinity, turbidity, temperature, dissolved oxygen, and pH. In some cases, a target site for olivine distribution and dissolution may be selected based on temporal heterogeneity compared to other candidate sites or baseline / reference sites.

[0148] As shown in Figures 29-31, in some cases, the methods disclosed herein may include calculating alkalinity fluxes and measuring olivine dissolution rates to secure carbon credits. The alkalinity flux contributed by olivine may be determined by distinguishing the change in alkalinity flux due to olivine from other natural background fluxes. In some cases, other fluxes attributed to olivine, such as dissolved inorganic carbon (DIC) flux and pCO2 flux, may be determined based on a comparison of the measured fluxes to natural background fluxes. The fluxes attributed to olivine dissolution and / or the natural background fluxes may be spatial and temporal dependent. Such spatial and temporal variations may be simulated, modeled, tracked, and / or measured to ensure accurate calculation of the fluxes attributed to olivine as opposed to the natural background fluxes.

[0149] In another aspect, the present disclosure provides various methods to take into account the heterogeneity of MRV. Figure 32 shows a summary of the MRV methods described below at different scales of cost and complexity. These methods can be used independently, in combination, or all together.

[0150] Method 1 - In some cases, the method may include using the shrinking core model described elsewhere herein to determine the approximate dissolution rate. The dissolution rate and the carbon dioxide / carbon removal sand ratio can be estimated or approximated.

[0151] Method 2 - Alternatively, mesocosm experiments may be utilized to determine regional olivine dissolution rates. Furthermore, this method can be initially tested using a closed, recirculating design configured to maintain and control spatiotemporal heterogeneity and also allow for temperature and / or lighting control.

[0152] When olivine is placed at a site of interest (e.g., in a mesocosm or natural environment), olivine tracers may be used to track olivine dissolution in order to model and refine in situ weathering rates.

[0153] The present disclosure provides systems and methods for tracking the movement of olivine particles in a location of interest. The systems and methods of the present disclosure may be implemented to track the movement of olivine in a location of interest based on or using, for example, trace metal content, fluorescent dyes, and / or olivine's unique spectral properties. This may be a relatively inexpensive process that can be set up prior to regulatory approval.

[0154] Method 3 - In some cases, the mesocosm-based methods described herein may be augmented with field data (e.g., obtained manually or automatically in situ using one or more sensors, or obtained ex situ by extraction of a representative field sample). Data obtained using one or more sensors (which may include any of the sensors described herein or any other sensors for obtaining any of the measurements referred to herein) may provide additional information to better quantify and track spatial and / or temporal variation in environmental conditions or parameters associated with olivine dissolution and coastal carbon capture.

[0155] Method 4 - In some cases, field-based methods may be used solely to obtain in situ data (e.g., in situ data obtained manually or automatically on-site using one or more sensors, or data obtained ex situ by extraction of a representative field sample). Data obtained using one or more sensors (which may include any of the sensors described herein or any other sensors for obtaining any of the measurements referred to herein) may provide sufficient information to quantify olivine dissolution, carbon removal, sediment transport, and track spatial and / or temporal variations in environmental conditions or parameters associated with olivine dissolution and coastal carbon capture.

[0156] Method 5 - In some cases, a numerical model may be constructed that can accurately simulate the spatial and temporal variations in background fluxes and olivine dissolution rates. This allows correction for time- and space-dependent variations, and sparse observations or other information or data at discrete points (e.g., points in time and / or points in space) may be used to calibrate, validate, and verify the model. The model may be constructed and run for one or more pre-simulations.

[0157] When olivine is placed in a natural environment, olivine tracers may be used to track olivine dissolution in order to estimate, predict, model, and refine in situ weathering rates.

[0158] The present disclosure provides systems and methods for tracking the movement or migration of olivine particles in a natural environment (e.g., a target location to which olivine is provided or introduced). The systems and methods of the present disclosure may be implemented to track the migration of olivine, for example, based on or using trace metal content, fluorescent dyes, and / or olivine's unique spectral properties. The trace metal content, the migration or dispersion of the fluorescent dyes, and / or the olivine's unique spectral properties may be detected and tracked using any of the sensors described herein.

[0159] Figure 33 shows various examples of reaction-transport modeling studies that can be used to simulate sediment porewater profiles, solid-phase chemistry, and benthic fluxes. Simulations and studies can be tailored to project requirements and can take into account secondary mineral formation, and trace metal speciation and cycling. The plots shown in Figure 33 show exemplary numerical simulations of alkalinity profiles and the effects of spreading a 2-centimeter (cm) thick layer of olivine sand on coastal sediments. In some cases, alkalinity fluxes across the sediment-water interface can be monitored by (1) building a biogeochemical model of olivine dissolution in the sediment, (2) validating model performance with field measurements of sediment-water alkalinity fluxes (and other carbonate parameters), and (3) calculating carbon dioxide capture, storage, or sequestration (by weight or volume) based on the thermodynamics of air-ocean carbon dioxide exchange and the known behavior of the marine carbonate system.

[0160] The systems and methods disclosed herein may be implemented with one or more sensors capable of measuring with optimal spatial and temporal resolution. As used herein, sensors may refer to sensors capable of remote sensing (including via buoys, drone surveys, etc.), benchtop sensors (i.e., traditional analytical devices), and other sensors. Sensors may eliminate the need to use traditional manual geochemical methods that require labor-intensive field sampling and shipping samples back to a lab for analysis, which may entail significant costs. FIG. 34 shows various examples of sensors that may be used for MRV, including sensors configured to measure temperature, salinity, pH, pCO2, DIC, alkalinity, redox, and / or wave effects on sand. In some cases, solid-state sensors for simultaneously measuring total alkalinity and pH of seawater (including seawater with or without olivine) may be used. In some embodiments, multiple sensors for MRV may be located in a single system. In other embodiments, multiple sensors for MRV may be located in multiple separate systems. Additional examples of sensors are shown in Figure 35, including silicate sensors, alkali sensors, CTDO sensors, Cytochips, dissolved inorganic carbon sensors, and nitrate sensors. 29 Si isotope tracers can be used to follow the precipitation of secondary clay and carbonate phases simultaneously with olivine dissolution, allowing the separation and tracking of total and net silicate dissolution.

[0161] In some cases, the effects of physical wave weathering on beach sands and olivine dissolution may be measured or simulated. In some cases, this may involve measuring and analyzing two-phase (i.e., sand-water) flow in the bottom boundary layer of breaking waves. This may be modeled numerically or physically (e.g., using wave tanks). In some cases, specialized sensors to measure turbulent energy dissipation (e.g., in a laboratory or directly on shore) may be utilized to measure the effects of physical wave weathering.

[0162] Figure 37 shows a method to measure carbon dioxide removal, made possible by the reactions shown in Figure 36. In some cases, it may not be possible to monitor the carbon dioxide flux from the atmosphere to the ocean. Measuring the carbon dioxide flux from the atmosphere to the ocean can be difficult because the olivine dissolution signal becomes very weak when diluted in open ocean waters. Measuring the net carbon dioxide flux is determined by measuring the ΔpCO due to changes in local photosynthesis and respiration. 2空気-海 This can be complicated by extreme seasonal and diurnal variations in alkalinity. Thus, in some embodiments, the systems and methods disclosed herein may be implemented to monitor alkalinity flux across the sediment-water interface.

[0163] In some cases, the models described herein (as may be generated for a particular site) may undergo a phase of testing, including validation. Such validation may include evaluating data sets such as topographic or geological features and their properties, hydrodynamic conditions, sediment movement, weather, olivine abundance, spatial distribution, i.e., olivine, non-olivine material and natural sediment, and / or dissolution rates, at one or more reference points in space and / or time. In some cases, the reference points may be arranged in a grid. Validation may further include validating the measured and modeled alkalinity flux and olivine dissolution at the reference points, and calculating the alkalinity flux for the region or project based on (i) the known mass or volume of olivine placed, and (ii) the validated site-specific modeling. The models may be validated using one or more sensor measurements, as described elsewhere herein. In some cases, the models may be validated using data from microcosms, mesocosms, and benthic flux chambers placed at or simulating field conditions where olivine is placed. Once validated, the models may be used to determine or predict olivine transport, olivine dissolution, reaction fluxes, and / or carbon sequestration. In some cases, the models may be updated or refined based on additional sensor measurements taken over a period of time or additional data obtained from field or laboratory experiments.

[0164] Figure 38 shows how to calculate carbon dioxide sequestration from alkalinity fluxes based on an equation for how the DIC storage of water changes as a function of increasing alkalinity. Ocean water carbonate chemistry can be controlled by pCO2, pH, DIC, and alkalinity. Under constant conditions of pCO2, temperature, and salinity, an isocapnic quotient can be calculated based on the change in alkalinity relative to the change in DIC. In some cases, a 1 micromole increase in alkalinity can result in a 0.78-0.93 micromole increase in DIC, meaning that for every ton of forsterite provided to a site of interest, 0.97-1.16 tons of carbon dioxide can be stored as marine DIC.

[0165] Figure 39 shows a plot of ocean water age and depth below sea surface as a function of latitude (northern). Carbon dioxide capture by ocean alkalinization requires that the alkalinized water masses come into equilibrium with atmospheric pCO2. The exact timescales of pCO2 equilibration (~4 months) and DIC adjustment (~4 years) depend on the Leber coefficient. The timescale of atmosphere-ocean equilibration is much shorter than the timescale of olivine dissolution (~10 to 100 years) and is roughly the same as the transit time distribution of the mixed layer and subtropical mode water (~10 to 40 years). This means that in equatorial and subtropical regions, the surface DIC reservoir can achieve quasi-stationary equilibrium, which is best suited for strong coastal weathering.

[0166] Life Cycle Analysis Once placed on a beach, carbon-removal sand can capture 20 times the carbon emitted during mining, crushing, transporting, and basic coastal projects. One tonne of carbon-removal sand can capture up to 1.25 tonnes of carbon in ideal conditions. Carbon-removal sand takes decades to weather, so it can provide effective coastal protection for long-term beach nourishment cycles.

[0167] The LCA evaluates the net carbon removal of a carbon removal project and encompasses both a quantification of the carbon removal from the placement of the carbon removal sand and the carbon dioxide or carbon dioxide equivalent emissions resulting from the placement. The total carbon removal of the project is primarily a function of the precise mineralogy of the carbon removal sand (e.g., Mg:Fe ratio in olivine), the purity of the carbon removal sand source (e.g., ratio of olivine to pyroxene), local seawater chemistry, grain size of the carbon removal sand, local seawater circulation patterns, and the extent of secondary mineral precipitation following placement of the carbon removal sand. Total carbon emissions may include emissions associated with mining and / or extraction of olivine, grinding the olivine to the required grain size, transporting the olivine to one or more target sites, and spreading the olivine at the target sites, as well as conducting monitoring for MRV purposes.

[0168] 40 shows an exemplary coastal carbon capture life cycle analysis. The life cycle may include mining and / or extraction of olivine, crushing the olivine to a desired particle size, transporting the olivine to one or more target locations, and spreading the olivine at the target locations. In some cases, the life cycle may be at least about 89% efficient and allow for the sequestration of at least about 5 to 20 times more carbon dioxide than is emitted during the mining, crushing, transporting, and / or spreading of the olivine.

[0169] Figure 41 shows an example of a carbon payback period that can be achieved using the methods and systems disclosed herein. In some cases, the break-even payback period can be about 4 years, assuming particle size: LE45 (d50: 365 μm), temperature: 25°C, pH: 8, embedded emissions: 110 tons of carbon dioxide / 1000 tons of olivine; absorption efficiency: 3 moles of ALK / 1 mole of olivine; dissolution constant: Log(r)=-8.75 (which can vary with pH / temperature).

[0170] Carbon Removal Projection In another aspect, the present disclosure provides systems and methods for predicting carbon removal rates at a particular location. Such predictions may be based on data corresponding to measurements of changes in alkalinity, pCO2, pH, and / or water temperature, for example. The predictions may be made using algorithms and software that interpret such data. The algorithms and software may be implemented by one or more models that may be generated based on MRV data obtained using various sensors, as described elsewhere herein.

[0171] In some embodiments, the predicted carbon removal rates may be used to provide information on how olivine sand properties and / or olivine sand preparation and deployment design may be optimized for improved / increased / more efficient carbon removal.

[0172] Computer Systems In one aspect, the present disclosure provides a computer system programmed or otherwise configured to implement any of the methods of the present disclosure, such as the subject methods for processing and dispersing olivine. FIG. 10 shows a computer system 1001 programmed or otherwise configured to implement a method for processing and dispersing olivine. The computer system 1001 may be configured, for example, to (i) identify a target location, (ii) optimize one or more procedures for processing olivine to provide advantageous properties or characteristics of olivine based on the identified target location, and (iii) coordinate transportation of olivine to the target location. The computer system 1001 may be a user's electronic device or a computer system located remotely relative to the electronic device. The electronic device may be a mobile electronic device.

[0173] The computer system 1001 may include a central processing unit (CPU, also referred to herein as a "processor" and a "computer processor") 1005, which may be a single-core processor or a multi-core processor, or multiple processors for parallel processing. The computer system 1001 may also include memory or memory locations 1010 (e.g., random access memory, read-only memory, flash memory), electronic storage 1015 (e.g., a hard disk), a communication interface 1020 (e.g., a network adapter) for communicating with one or more other systems, and peripheral devices 1025, such as cache, other memory, data storage adapters, and / or electronic display adapters. The memory 1010, storage 1015, interface 1020, and peripheral devices 1025 communicate with the CPU 1005 via a communication bus (solid lines), such as a motherboard. The storage 1015 may be a data storage device (or data repository) for storing data. The computer system 1001 may be operatively coupled to a computer network ("network") 1030 with the aid of the communication interface 1020. The network 1030 may be the Internet, an Internet and / or an extranet, or an intranet and / or an extranet in communication with the Internet. The network 1030 may be a telecommunications network and / or a data network in some cases. The network 1030 may include one or more computer servers, which may enable distributed computing, such as cloud computing. The network 1030 may, in some cases, implement a peer-to-peer network with the aid of the computer system 1001, which may enable devices coupled to the computer system 1001 to operate as clients or servers.

[0174] The CPU 1005 can execute sequences of machine-readable instructions, which may be embodied in a program or software. The instructions may be stored in a memory location, such as the memory 1010. The instructions may instruct the CPU 1005, which may then be programmed or otherwise configured to perform the methods of the present disclosure. Examples of operations performed by the CPU 1005 may include fetch, decode, execute, and writeback.

[0175] The CPU 1005 may be part of a circuit, such as an integrated circuit. One or more other components of the system 1001 may be included in the circuit. In some cases, the circuit is an application specific integrated circuit (ASIC).

[0176] The storage device 1015 can store files such as drivers, libraries, and saved programs. The storage device 1015 can store user data, such as user preferences and user programs. The computer system 1001 can optionally include one or more additional data storage devices located outside the computer system 1001 (e.g., on a remote server in communication with the computer system 1001 via an intranet or the Internet).

[0177] The computer system 1001 can communicate with one or more remote computer systems via the network 1030. For example, the computer system 1001 can communicate with a remote computer system of a user (e.g., an end user performing or monitoring the processing and / or transportation or dispersal of olivine). Examples of remote computer systems include personal computers (e.g., portable PCs), slate or tablet PCs (e.g., Apple iPad®, Samsung Tab), phones, smartphones (e.g., Apple iPhone®, Android®-enabled devices, Blackberry), or personal digital assistants. A user can access the computer system 1001 via the network 1030.

[0178] The methods described herein may be implemented by machine (e.g., a computer processor) executable code stored in an electronic storage location of the computer system 1001, such as, for example, memory 1010 or electronic storage 1015. The machine executable or machine readable code may be provided in the form of software. In use, the code may be executed by the processor 1005. In some cases, the code is retrieved from storage 1015 and stored in memory 1010 for ready access by the processor 1005. In some cases, the electronic storage 1015 is not used and the machine executable instructions may be stored in memory 1010.

[0179] The code can be precompiled and configured or compiled during run-time for use with a machine having a processor adapted to execute the code. The code can be provided in a programming language that can be selected so that the code can be executed in a precompiled or compiled fashion.

[0180] Aspects of the systems and methods provided herein, such as the computer system 1001, may be embodied in programming. Various aspects of the technology may be considered as a "product" or "article of manufacture" in the form of machine (or processor) executable code and / or associated data typically carried on or embodied in a type of machine-readable medium. The machine-executable code may be stored in an electronic storage device, such as a memory (e.g., read-only memory, random access memory, flash memory) or a hard disk. A "storage" type medium may include tangible memory of a computer, a processor, or any or all of its associated modules, such as various semiconductor memories, tape drives, disk drives, etc., that may provide non-transitory storage for software programming at any time. All or part of the software may be communicated over the Internet or various other remote communication networks. Such communication may enable loading of the software from one computer or processor to another, such as, for example, from a management server or host computer to a computer platform of an application server. Thus, other types of media that may carry software elements include optical, electrical, and electromagnetic waves, for example, used over physical interfaces between local devices, over wired and optical fixed line networks, and over various air links. Physical elements that transmit such waves, such as wired or wireless links, optical links, etc., may also be considered to be media carrying software. As used herein, unless limited to non-transitory tangible "storage" media, terms such as computer or machine "readable medium" refer to any medium that participates in providing instructions to a processor for execution.

[0181] Thus, a machine-readable medium such as a computer executable code can take many forms including, but not limited to, a tangible storage medium, a carrier wave medium, or a physical transmission medium. Non-volatile storage media including, for example, optical or magnetic disks, or any storage device in any computer(s), may be used to implement the databases and the like shown in the figures. Volatile storage media include dynamic memory such as the main memory of such a computer platform. Tangible transmission media include coaxial cables, copper wire and optical fibers, including the wires that make up a bus in a computer system. Carrier wave transmission media can take the form of electric or electromagnetic signals, or acoustic or light waves such as those generated during radio frequency (RF) and infrared (IR) data communications. Thus, common forms of computer readable media include, for example, floppy disks, flexible disks, hard disks, magnetic tape, other magnetic media, CD-ROMs, DVDs or DVD-ROMs, other optical media, punch cards paper tape, other physical storage media with patterns of holes, RAM, ROM, PROMs and EPROMs, FLASH-EPROMs, other memory chips or cartridges, carrier waves carrying data or instructions, cables or links carrying such carrier waves, or other media from which a computer can read programming code and / or data. Many of these forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to a processor for execution.

[0182] The computer system 1001 may include or communicate with an electronic display 1035 with a user interface (UI) 1040 to provide a user with a portal for monitoring, for example, the processing and / or transportation or dispersal of olivine. The portal may be provided via an application programming interface (API). A user or entity may also interact with various elements within the portal via the UI. Examples of UIs include, but are not limited to, graphical user interfaces (GUIs) and web-based user interfaces.

[0183] The methods and systems of the present disclosure may be implemented by one or more algorithms. The algorithms may be implemented by software when executed by the central processing unit 1005. For example, an algorithm may be configured to identify a site of interest and optimize a procedure for processing olivine based on properties or characteristics of the site of interest.

[0184] Although preferred embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the present invention be limited by the specific examples provided herein. Although the present invention has been described with reference to the foregoing specification, the description and illustration of the embodiments herein are not intended to be construed in a limiting sense. Numerous variations, changes, and substitutions will occur to those skilled in the art without departing from the present invention. Furthermore, it should be understood that all aspects of the present invention are not limited to the specific depictions, configurations, or relative proportions set forth herein, which depend upon a variety of conditions and variations. It should be understood that various alternatives to the embodiments of the present invention described herein may be employed in the practice of the present invention. It is therefore contemplated that the present invention will cover such alternatives, modifications, variations, or equivalents. It is intended that the following claims define the scope of the present invention, and that methods and structures within the scope of these claims and their equivalents are covered thereby.

Claims

[Claim 1] 1. A method for quantifying carbon sequestration resulting from dissolution of carbon removal sand, comprising: a. (i) obtaining one or more measurements from at least one sensor, or (ii) obtaining one or more readings from at least one meter; b) validating or updating one or more models for determining or predicting one or more chemical fluxes associated with the movement of the carbon-removing sand, the dissolution of the carbon-removing sand, carbon sequestration due to the carbon-removing sand, or the dissolution of the carbon-removing sand in a target environment based on the one or more measurements or readings; c. using the one or more models to determine or predict carbon dioxide removal, the one or more models generating at least a project-wide spatial-temporal atmospheric carbon dioxide removal, the one or more models comprising a sand transport, sand dissolution, carbon sequestration, or chemical flux model; d. calculating net atmospheric carbon dioxide reductions by subtracting the project emissions identified through the project-specific life cycle analysis from the total atmospheric carbon dioxide reductions; A method comprising:

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