EP4626849A2

EP4626849A2 - Systems and methods for carbon sequestration with organic matter sulfurization

Info

Publication number: EP4626849A2
Application number: EP23898945.3A
Authority: EP
Inventors: Morgan RAVEN
Original assignee: University of California; University of California Berkeley; University of California San Diego UCSD
Current assignee: University of California; University of California Berkeley; University of California San Diego UCSD
Priority date: 2022-12-01
Filing date: 2023-11-30
Publication date: 2025-10-08
Also published as: GEAP202516693A; WO2024118990A2; WO2024118990A3

Abstract

Methods and systems for terrestrial biomass sulfurization are provided. The sulfurization processes can react with the carbon sources in the biomass and preserve the carbon to promote the carbon removal efficiency. The sulfurization processes can enhance the storage efficiency of terrestrial biomass in anoxic aqueous environments.

Description

SYSTEMS AND METHODS FOR CARBON SEQUESTRATION WITH ORGANIC MATTER SULFURIZATION

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The current application claims the benefit and priority of U.S. Provisional Patent Application No. 63/429,477 entitled “Systems and Methods for Marine Carbon Sequestration with Organic Matter Sulfurization” filed December 1 , 2022. The disclosure of U.S. Provisional Patent Application No. 63/429,477 is incorporated by reference in its entirety for all purposes.

FIELD OF THE INVENTION

[0002] The current disclosure is directed to systems and methods for carbon sequestration; and more particularly to systems and methods for using organic matter sulfurization for marine carbon sequestration.

BACKGROUND

[0003] Due to continuing human emissions of CO2 from fossil fuel burning and land use change, atmospheric CO2 concentrations have dramatically increased over the preindustrial conditions, driving demonstrable changes in global temperatures, precipitation, storm intensity, ocean pH, and the biological processes that depend on these parameters. Active carbon dioxide removal (CDR) can be necessary alongside drastic emissions reductions to keep the increase in mean global temperatures below 1.5 °C and avoid severe consequences of climate change. While efforts have been made to develop CDR methods that aim to cultivate and sink marine macroalgae, less attention has been paid to storage of terrestrial biomass in aqueous systems. In both cases, the major environmental risks associated with sinking and sequestering biomass stem from the breakdown and oxidation of that biomass to release CO2, nutrients, and protons (pH change). Therefore, a primary objective of CDR technology development can be to minimize rates of biomass breakdown during storage. BRIEF SUMMARY

[0004] Systems and methods in accordance with various embodiments of the invention implement organic matter sulfurization for marine carbon sequestration. The use of organic matter sulfurization for carbon sequestration can enhance the storage efficiency of biomass in anoxic aqueous environments. Many embodiments can achieve atmospheric carbon dioxide removal and negative carbon dioxide emissions. Several embodiments provide processes for the geological sequestration of organic carbon- containing materials.

[0005] Several embodiments accelerate the natural organic matter sulfurization processes by combining with industrial scale agriculture and/or aquaculture. In some embodiments, bales of biomass (such as corn stover) can be shipped by barge to a naturally anoxic-to-sulfidic basin. The bales can be densified and/or weighted with ballast and sunk to greater than about 400 meters depth. Choice of sequestration locations can be naturally sulfidic locations, or can be anoxic and poised to support the formation of sulfidic environments within bales. In certain embodiments, sulfide can serve as a natural preservative. Microbes may not be able to access the sulfurized organic carbon such that rates of the sulfurized carbon breakdown are significantly lower than they would be in the absence of sulfurization. To maintain the system at stable redox and chemical conditions, several embodiments monitor sequestration locations for their pH and sulfide concentrations using a variety of sensors such as (but not limited to) optical sensors and/or voltammetry sensors.

[0006] Some embodiments include a method for carbon sequestration comprising: exposing a biomass material comprising carbon to a sulfur source in an aqueous environment such that the carbon is sulfurized by the sulfur source via a sulfurization reaction to form a sulfurized carbon in the aqueous environment.

[0007] In some embodiments, the biomass material comprises an organic material derived from a source selected from the group consisting of: an agricultural product, a tree, wood, grass, an animal, an alga, and a microbial cell.

[0008] In some embodiments, the biomass material comprises corn stover. [0009] In some embodiments, the biomass material comprises polysaccharide, monosaccharide, glycan, starch, sugar, hemicellulose, or lipid.

[0010] In some embodiments, the carbon is a part of a functional group selected from the group consisting of: a conjugated double bond, a carbonyl, and an aldehyde.

[0011] In some embodiments, the sulfurization reaction adds sulfur to the biomass material by forming alkyl sulfides and alkyl disulfides.

[0012] In some embodiments, the aqueous environment comprises anoxic water.

[0013] In some embodiments, the aqueous environment comprises sulfidic water or dissolved sulfur as the sulfur source.

[0014] In some embodiments, the sulfurized carbon comprises a functional group selected from the group consisting of: monosulfide, disulfide, polysulfide, sulfoxide, sulfonate, and aromatic sulfur.

[0015] In some embodiments, the sulfur source dissolves in the aqueous environment. [0016] Some embodiments further comprise creating a bundle of the biomass material.

[0017] In some embodiments, the bundle of the biomass material is configured to sink into the aqueous environment.

[0018] In some embodiments, the bundle comprises a plurality of pores and a packing tightness of the bundle is adjustable to control a water advection rate through the plurality of pores within the bundle.

[0019] In some embodiments, the controlled water advection rate generates sulfides in the plurality of pores such that the sulfides drive the sulfurization reaction.

[0020] Some embodiments further comprise adding microbial sulfate reducing microorganisms to the biomass material.

[0021] In some embodiments, the biomass material is a terrestrial biomass material.

[0022] Additional embodiments and features are set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the specification or may be learned by the practice of the disclosed subject matter. A further understanding of the nature and advantages of the present disclosure may be realized by reference to the remaining portions of the specification and the drawings, which form part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The description will be more fully understood with reference to the following figures, which are presented as exemplary embodiments of the invention and should not be construed as a complete recitation of the scope of the invention. It should be noted that the patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0024] FIGs. 1A through 1 C illustrate sulfurization reactions in accordance with prior art.

[0025] FIGs. 2A through 2F illustrate accumulation of organic sulfides and disulfides in corn stover when exposed to a sulfur source in accordance with an embodiment of the invention.

[0026] Figure 3 conceptually illustrates a process for in situ sulfurization of sequestered biomass in accordance with an embodiment of the invention.

DETAILED DESCRIPTION

[0027] In this disclosure, sulfides refer to three classes of chemical compounds containing sulfur: inorganic sulfides, organic sulfides, and polysulfides. Inorganic sulfides include ionic compounds containing the negatively charged sulfide ion S^2-. Examples of inorganic sulfides include (but not limited to) dissolved sulfide (HS‘) or polysulfide (Sn^2-). Organic sulfides include compounds in which a sulfur atom is covalently bonded to two organic groups.

[0028] Turning to the drawings, descriptions of carbon sequestration using organic matter sulfurization are provided. Many embodiments provide methods for removing carbon dioxide from aqueous environment. Sulfurization processes can preserve organic carbon from biomass and limit the amount of carbon that might be released. Biomass can be organic materials derived from living organisms including (but not limited to) agricultural products, plants, trees, grasses, animals, algal cells, and microbial cells. Examples of agricultural products include (but are not limited to) corn stover, sugar cane residual materials. Several embodiments implement chemical sulfurization of biomass via placement of biomass within naturally sulfidic waters and/or facilitation of microbial sulfate reduction within accumulations of biomass materials. Sulfurization reactions can have fast reaction times under desired environments and reaction conditions. Several embodiments implement pretreatment and/or preparation of biomass before starting the sulfurization processes to maximize the reaction efficiency. In many embodiments, sulfurization can be induced within bales and tuned to match the availability of sulfate. In some embodiments, the packing tightness of bales can be adjusted to limit rates of advection of water through the pore spaces within the bales. In several embodiments, microbial sulfate reducing microorganisms can be introduced to the bale pore spaces through the bale from the environment during sinking and placement, and/or via addition of small amounts of sediment. The sediments can be collected below or proximal to the biomass storage site. The biomass storage site may contain living microbial communities including (but not limited to) sulfate reducing microorganisms.

[0029] Strategies to minimize rates of biomass breakdown during lacustrine and marine storage can operationalize observations of natural Earth processes. Biomass burial in marine and lacustrine sediments is one of the two principal mechanisms that the Earth system can use to remove excess CO2 from its atmosphere over geologic timescales (thousands of years or more). This process naturally buries about 0.8 Petagram (Pg, also known as Gigaton or Gt) carbon (C) globally each year, most of which can be concentrated in ‘hotspots’ of C burial near coasts and in parts of the ocean with relatively low concentrations of dissolved O2. Natural processes that are characteristic of hotspots of C burial may serve as analogs to guide the development of biomass sequestration methods that operate at a larger scale desired to mitigate anthropogenic emissions.

[0030] Organic matter sulfurization refers to a suite of chemical reactions between specific organic functional groups including (but not limited to) aldehydes, carbonyls, conjugated double bonds, and dissolved sulfide (HS ) or polysulfide (Sn² ). Naturally sulfurized products are present in petroleum and organic carbon-rich rocks. Organic matter sulfurization process can contribute to the efficient preservation of organic carbon because it can reduce the accessibility of organic molecules to microbial exoenzymes, decrease solubility and increase molecular weight. Sulfurization may occur from days to weeks given sulfide concentrations in the pM to mM range. However, sulfurization reactions have not been applied in industrial scales to modify the properties and/or breakdown kinetics of organic matter.

[0031] Figure 1 illustrates sulfurization mechanisms of major biomass components. Figure 1A shows sulfurization mechanism of monosaccharides. Figure 1 B shows sulfurization mechanism of lipids with carbonyl functionalities (a,[3-unsaturated isoprenoid aldehyde). The wavy lines indicate an extended organic polymer network. Figure 1 C illustrates sulfurization mechanism of lipids with conjugated double bonds (unsaturated tricyclic triterpenoid). (See, e.g., J.P. Werne, et al., Geochimica et Cosmochimica Acta, 64, 10, 2000, 1741-51 ; B.E. van Dongen, et al., Organic Geochemistry, 34, 8, 2003, 1129- 44; Amrani, et al., Organic Geochemistry, 35, 8, 2004, 909-21 ; the disclosures of which are incorporated herein by references.)

[0032] Many embodiments implement chemical sulfurization of biomass to enhance the preservation of organic carbon stored in aqueous environments. Examples of the aqueous environments include (but are not limited to) lakes, rivers, ponds, oceans, and reservoirs. Chemical sulfurization can include a suite of reactions between organic matter and sulfide and/or polysulfides. Biomass can be organic materials derived from living organisms including (but not limited to) agricultural products, plants, trees, grasses, animals, algal and microbial cells. Examples of agricultural products include (but are not limited to) corn stover, sugar cane residual materials. In several embodiments, chemical sulfurization of biomass can be achieved through (1 ) placement of biomass within naturally sulfidic waters and/or (2) facilitation of microbial sulfate reduction within accumulations of biomass materials. Chemical sulfurization in accordance with some embodiments can be used to enhance the sequestration efficiency of biomass for durable (greater than about 1 ,000 years) organic carbon storage in aqueous environments. Slower remineralization rates of sequestered biomass may minimize the environmental risks of biomass sinking and storage, including acidification and the release of nutrients, CO2, and methane. Some embodiments provide that the chemical sulfurization may increase carbon sequestration efficiency for CO2 credits.

[0033] In many embodiments, biomass sulfurization can target specific components of biomass that are highly reactive. In certain embodiments, the highly reactive biomass components can contain reactive functional groups including (but not limited to) conjugated double bonds, carbonyls, and aldehydes. The highly functionalized molecules that can be sulfurized can also be rapidly re-mineralized (consumed by organisms and oxidized to CO2) in the environment. For example, glucose can be rapidly re-mineralized in most environments and can also be sulfurized experimentally within weeks. In contrast, lignin (woody materials) break down much more slowly. Therefore, relatively limited but targeted sulfurization can have a positive effect on the overall remineralization / breakdown rate of biomass by preserving the components that would otherwise be remineralized.

[0034] Several embodiments use sulfurization reactions with biomass to capture carbon. Some embodiments show the sulfurization reactions within forms of biomass with high CDR potential. Figures 2A through 2F illustrate accumulation of organic sulfides and disulfides in corn stover in accordance with an embodiment of the invention. Figures 2A through 2F show accumulation of organic sulfides and disulfides in corn stover following exposure to about 0 pM, about 400 pM, or about 800 pM polysulfides for about 5 days under conditions similar to modern sulfidic basins (about 8 °C, pH about 8, artificial seawater). Com stover can be y-irradiated (sterilized to exclude microbial processes), ground, and separated into larger (woody) and smaller (pithy) fractions before incubation. The organic sulfur products can be monosulfide, disulfide, polysulfide, sulfoxide, sulfonate, or aromatic sulfur. Figure 2A shows X-ray absorption spectra for organic sulfur standards used in fitting. Figures 2B and 2C show normalized spectra for the larger (greater than about 180 microns) and smaller (less than about 180 microns) fractions of ground corn stover following exposure to about 0 pM, about 400 pM, or about 800 pM polysulfides for about 5 days. Corn stover exposed to polysulfides have increased amounts of organic sulfur than untreated corn stover. Figure 2D shows molar sulfur to carbon (S:C) ratios in corn stover before and after incubation with polysulfides. Figures 2E and 2F show relative abundance of organic S species based on a linear fitting of spectra in Figures 2B and 2C based on standards in Figure 2A. Fit uncertainties can be about 1 -2%. The increase in molar elemental ratios from the control sample to the polysulfide-exposed sample represents the formation of organic sulfur from dissolved sulfide and/or polysulfide. X-ray absorption spectroscopy confirms the addition of organic disulfides to the corn stover over the course of the measurement. Many embodiments apply the observation that that reactive components of terrestrial biomass sulfurize when exposed to sulfide and/or polysulfide. Sulfurization products can be chemically analogous to organic materials preserved in marine sediments over geologic timescales (thousands of years or more).

[0035] In many embodiments, sulfurization can be induced within bales and tuned to match the availability of sulfate. In a number of embodiments, bale preparation can include packing and wrapping with burlap, twine, or similar plant fiber mesh. Packing tightness can be adjusted to limit rates of advection of water through the pore spaces within the bales in accordance with certain embodiments. Managed rates of advection can generate larger regions of sulfidic pore water. Microbial sulfate reducing microorganisms in accordance with several embodiments can be introduced to the bale pore spaces from the flushing of water through the bale from the environment during sinking and placement, and/or via addition of small amounts of sediment, collected below or proximal to the biomass storage site, that contains living microbial communities including sulfate reducing microorganisms.

[0036] Figure 3 conceptually illustrates a process for in situ sulfurization of sequestered biomass in accordance with an embodiment. Baled or otherwise contained (such as bundled) biomass can be exposed to sulfides and/or polysulfides during sinking and storage in sulfidic basins, driving sulfurization reactions. Biomass sulfurization can add sulfur to biomass in the forms of alkyl sulfides and disulfides and increase the longterm preservation potential of functional organic materials including (but not limited to) starch, hemicellulose, and lipids. [0037] In several embodiments, agricultural biomass can be placed at the sedimentwater interface of a sulfidic basin (such as the Black Sea). In some embodiments, biomass can be quantified (weighed), baled, and sunk using ballast, e.g. waste concrete, into sulfidic water. Sulfidic water can be used as a natural source of sulfide (mostly HS') for sulfurization reactions. Reactive components of the biomass including (but not limited to) polysaccharides, monosaccharides, glycans, sugars, lipids, and cell membrane lipids, can be modified by reaction with dissolved sulfide and/or polysulfides. Sulfurization can be measured through chemical analysis of the resulting biomass. Examples of sulfurization reactions are shown in Figure 1 .

[0038] In many embodiments, sulfidic conditions can be cultivated within baled biomass. In certain embodiments, biomass can be quantified (weighed), baled, and sunk using ballast into anoxic but non-sulfidic water (sulfide concentrations near or below detection limits (less than about 3 pM). Bale packing tightness can be adjusted to limit rates of advection of water through the pore spaces within the bales. Managed rates of advection can generate larger regions of sulfidic pore water. Sulfide generated within the bale pore spaces can drive sulfurization reactions in accordance with several embodiments. Reactive components of the biomass, e.g., sugars and cell membrane lipids, can be modified by reaction with dissolved sulfur species. Sulfurization is measured through chemical analysis of the resulting biomass.

EXAMPLES

[0039] Example 1 : A method for carbon sequestration comprising: exposing a biomass material comprising carbon to a sulfur source in an aqueous environment such that the carbon is sulfurized by the sulfur source via a sulfurization reaction to form a sulfurized carbon in the aqueous environment.

[0040] Example 2: The method of example 1 , wherein the biomass material comprises an organic material derived from a source selected from the group consisting of: an agricultural product, a tree, wood, grass, an animal, an alga, and a microbial cell.

[0041] Example 3: The method of example 1 or 2, wherein the biomass material comprises corn stover. [0042] Example 4: The method of example 1 , or 2, or 3, wherein the biomass material comprises polysaccharide, monosaccharide, glycan, starch, sugar, hemicellulose, or lipid.

[0043] Example 5: The method of any one of examples 1 to 4, wherein the carbon is a part of a functional group selected from the group consisting of: a conjugated double bond, a carbonyl, and an aldehyde.

[0044] Example 6: The method of any one of examples 1 to 5, wherein the sulfurization reaction adds sulfur to the biomass material by forming alkyl sulfides and alkyl disulfides. [0045] Example 7: The method of any one of examples 1 to 6, wherein the aqueous environment comprises anoxic water.

[0046] Example 8: The method of any one of examples 1 to 7, wherein the aqueous environment comprises sulfidic water or dissolved sulfur as the sulfur source.

[0047] Example 9: The method of any one of examples 1 to 8, wherein the sulfurized carbon comprises a functional group selected from the group consisting of: monosulfide, disulfide, polysulfide, sulfoxide, sulfonate, and aromatic sulfur.

[0048] Example 10: The method of any one of examples 1 to 9, wherein the sulfur source dissolves in the aqueous environment.

[0049] Example 11 : The method of any one of examples 1 to 10, further comprising creating a bundle of the biomass material.

[0050] Example 12: The method of any one of examples 1 to 11 , wherein the bundle of the biomass material is configured to sink into the aqueous environment.

[0051] Example 13: The method of any one of examples 1 to 12, wherein the bundle comprises a plurality of pores and a packing tightness of the bundle is adjustable to control a water advection rate through the plurality of pores within the bundle.

[0052] Example 14: The method of any one of examples 1 to 13, wherein the controlled water advection rate generates sulfides in the plurality of pores such that the sulfides drive the sulfurization reaction.

[0053] Example 15: The method of any one of examples 1 to 14, further comprising adding microbial sulfate reducing microorganisms to the biomass material. [0054] Example 16: The method of any one of examples 1 to 15, wherein the biomass material is a terrestrial biomass material.

DOCTRINE OF EQUIVALENTS

[0055] As can be inferred from the above discussion, the above-mentioned concepts can be implemented in a variety of arrangements in accordance with embodiments of the invention. Accordingly, although the present invention has been described in certain specific aspects, many additional modifications and variations would be apparent to those skilled in the art. It is therefore to be understood that the present invention may be practiced otherwise than specifically described. Thus, embodiments of the present invention should be considered in all respects as illustrative and not restrictive.

[0056] As used herein, the singular terms "a," "an," and "the" may include plural referents unless the context clearly dictates otherwise. Reference to an object in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more."

[0057] As used herein, the terms “approximately,” and "about" are used to describe and account for small variations. When used in conjunction with an event or circumstance, the terms can refer to instances in which the event or circumstance occurs precisely as well as instances in which the event or circumstance occurs to a close approximation. When used in conjunction with a numerical value, the terms can refer to a range of variation of less than or equal to ± 10% of that numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1 %, less than or equal to ±0.5%, less than or equal to ±0.1 %, or less than or equal to ±0.05%.

[0058] Additionally, amounts, ratios, and other numerical values may sometimes be presented herein in a range format. It is to be understood that such range format is used for convenience and brevity and should be understood flexibly to include numerical values explicitly specified as limits of a range, but also to include all individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly specified. For example, a ratio in the range of about 1 to about 200 should be understood to include the explicitly recited limits of about 1 and about 200, but also to include individual ratios such as about 2, about 3, and about 4, and sub-ranges such as about 10 to about 50, about 20 to about 100, and so forth.

Claims

CLAIMS:

1. A method for carbon sequestration comprising: exposing a biomass material comprising carbon to a sulfur source in an aqueous environment such that the carbon is sulfurized by the sulfur source via a sulfurization reaction to form a sulfurized carbon in the aqueous environment.

2. The method of claim 1 , wherein the biomass material comprises an organic material derived from a source selected from the group consisting of: an agricultural product, a tree, wood, grass, an animal, an alga, and a microbial cell.

3. The method of claim 1 , wherein the biomass material comprises corn stover.

4. The method of claim 1 , wherein the biomass material comprises polysaccharide, monosaccharide, glycan, starch, sugar, hemicellulose, or lipid.

5. The method of claim 1 , wherein the carbon is a part of a functional group selected from the group consisting of: a conjugated double bond, a carbonyl, and an aldehyde.

6. The method of claim 1 , wherein the sulfurization reaction adds sulfur to the biomass material by forming alkyl sulfides and alkyl disulfides.

7. The method of claim 1 , wherein the aqueous environment comprises anoxic water.

8. The method of claim 1 , wherein the aqueous environment comprises sulfidic water or dissolved sulfur as the sulfur source.

9. The method of claim 1 , wherein the sulfurized carbon comprises a functional group selected from the group consisting of: monosulfide, disulfide, polysulfide, sulfoxide, sulfonate, and aromatic sulfur. The method of claim 1 , wherein the sulfur source dissolves in the aqueous environment. The method of claim 1 , further comprising creating a bundle of the biomass material. The method of claim 11 , wherein the bundle of the biomass material is configured to sink into the aqueous environment. The method of claim 11 , wherein the bundle comprises a plurality of pores and a packing tightness of the bundle is adjustable to control a water advection rate through the plurality of pores within the bundle. The method of claim 13, wherein the controlled water advection rate generates sulfides in the plurality of pores such that the sulfides drive the sulfurization reaction. The method of claim 1 , further comprising adding microbial sulfate reducing microorganisms to the biomass material. The method of claim 1 , wherein the biomass material is a terrestrial biomass material.