Carbon storing element

Abstract

A carbon-storing element (0) comprising a storage body (1) and a barrier layer (2), wherein the storage body (1) is formed of a storage body composition comprising an at least partially carbonized material, optionally in combination with a binder material, characterized in that the barrier layer encapsulates the storage body.

Description

[0001] TITLE

[0002] CARBON STORING ELEMENT

[0003] TECHNICAL FIELD

[0004] The present invention relates to carbon sequestration, and in particular relates to a novel carbon storing element, its process of production, as well as to its use in long-term carbon storage.

[0005] PRIOR ART

[0006] Carbon dioxide (CO2) is a greenhouse gas which is released into the earth's atmosphere primarily when combustible fuels such as biomass, petrochemically produced liquid fuels, coal, natural gas and other hydrocarbons react with oxygen and release water and carbon dioxide. This is most commonly the case when fuels are burned or when atmospheric oxygen reacts with carbonaceous material such as coal or peat.

[0007] Because carbon dioxide is one of the greenhouse gases that are produced in large quantities, it is desirable to provide strategies that can help with eliminating or reducing the generation of carbon dioxide, in order to reduce the greenhouse effect in the earth's atmosphere. However, a reduction of carbon dioxide emissions is but one lever that can be used to reduce the concentration of carbon dioxide in the atmosphere back to preindustrial levels. The active sequestration of carbon dioxide from the atmosphere or biosphere is equally important if global warming is to be stopped or reversed.

[0008] Sequestering of carbon dioxide is a process known in nature, as plants can fix carbon dioxide molecules in carbohydrate molecules via photosynthesis and marine organisms produce shells or coral made of calcium carbonate by fixing carbon dioxide dissolved in the ocean water.

[0009] Carbon fixation in plants or animals is however only transient, since organisms eventually die and are decomposed by fungi, microorganisms and invertebrates that release the carbon dioxide back into the atmosphere.

[0010] For centuries, plant matter was made into coal by either pyrolytic or hydrothermal processing. Coal is essentially elemental carbon and has been used as fuel in stoves, kilns, hearths or foundries since times immemorial.

[0011] However, coal production from plant material can also be used as a carbon sink, provided that the produced coal is not burned or otherwise oxidized. T o this end, it has been proposed to store coal in environments that are not amenable to coal combustion or oxidation, such as abandoned mines which offer underground mine shafts or open mine pits, where oxygen availability is limited and where, in the absence of dewatering, water slowly floods the shaft or pit.

[0012] It is worth noting that coal must not necessarily burn, in the common sense, to release carbon dioxide. At ambient conditions, coal or peat may spontaneously react exothermically with atmospheric oxygen to form carbon dioxide. While this reaction, in itself, does not constitute a fire hazard, the accumulation of the heat released during that reaction can lead to ignition of the coal or peat if the heat cannot be dissipated.

[0013] Thus, when considering long-term storage of coal for the sake of carbon capture, it is necessary to provide a technical solution that protects the coal to be stored against oxidation, be it slow atmospheric oxidation or fast combustion, for centuries or even millennia. At the same time, the technical solution should be implementable with existing apparatuses used in the field of coal production and with minor investment.

[0014] WO2022 / 159602A1 discloses pellets made from plant materials which a highly grindable. While biocarbon pellets can be transported conveniently, pellets must be ground into smaller particles for the purpose of increasing the available surface for combustion at the site of use, such as a blast furnace of a steelworks. The grindability of the pellets is achieved by the admixture of binders to the coal during pellet formation, that can be or comprise reactivity-moderating agents. In one embodiment, the binder can be disposed on the surfaces of the biocarbon pellets and fully encapsulates the biocarbon pellet, forming a surface coating on each pellet [0107 / 0108],

[0015] SUMMARY OF THE INVENTION It is an objective of the present invention to provide an carbon-storing element for the storage of carbon that is stable over extended periods of time, as well as a method of manufacturing such an element from carbonized material, and which element can be of added benefit beyond the sole use of carbon storage as a replacement material in construction.

[0016] Accordingly, it is a first object of the present invention to provide a carbon-storing element comprising a storage body and a barrier layer, is formed of a storage body composition comprising an at least partially carbonized material, optionally in combination with a binder material, characterized in that the barrier layer encapsulates the storage body.

[0017] Further embodiments of the invention are laid down in the dependent claims.

[0018] BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Preferred embodiments of the invention are described in the following with reference to the drawings, which are for the purpose of illustrating the present preferred embodiments of the invention and not for the purpose of limiting the same. In the drawings,

[0020] Fig. 1 shows a schematic depiction of a carbon-storing element (0) according to the invention comprising a storage body (1) and a barrier layer (2), which barrier layer encapsulates the storage body.

[0021] Fig. 2 shows a schematic depiction of a plurality of carbon-storing elements (0) comprising a storage body (1) and a barrier layer (2), in a layer of compacted carbon-storing elements with little interstitial space between carbon-storing elements (0).

[0022] Fig. 3 shows a schematic depiction of a bulk aggregate for construction comprising a plurality of loose carbon-storing elements (0) comprising a storage body (1) and a barrier layer (2), in combination with mineral construction aggregate (3) such as clay.

[0023] Fig. 4 shows a photograph of a plurality of carbon-storing elements having a roughly cylindrical shape. The barrier layer is visible and is formed from a silicone rubber coated onto the storage body, such as to encapsulate the storage body.

[0024] Fig. 5 shows a photograph of cross-section of a carbon-storing elements. The barrier layer coated on the surface of the storage body is visible and encapsulates the storage body.

[0025] DESCRIPTION OF PREFERRED EMBODIMENTS

[0026] Accordingly, it is a first object of the present invention to provide a carbon-storing element comprising a storage body and a barrier layer, is formed of a storage body composition comprising an at least partially carbonized material, optionally in combination with a binder material, and / or wherein the storage body has a total carbon content (TC) of at least 10% by weight, based on the weight of the storage body, characterized in that the barrier layer encapsulates the storage body. Thus, in opposition to a combustible carbon-storing elements such as the carbon-storing elements known in the art, the carbon-storing element is not suitable for combustion or disintegration for combustion.

[0027] The carbon storing element according to the present invention is suitable for long-term storage, in particular in the geosphere or the lithosphere. While the size of the carbon storing element is not particularly limited, the carbon storing element is preferably sized such that it may manipulated, transported and deposited in bulk form such as pellets especially when it is used as replacement for mineral aggregate.

[0028] The carbon-storing element comprises a storage body. The storage body comprises the majority of, or essentially consists of, the carbon that is stored in the carbon-storing element of the present invention. Except for the requirement that a certain level of carbon must be comprised in the storage body, the composition of the storage body is not particularly limited. Thus, the storage body is made of a storage body composition, which storage body composition comprises an at least partially carbonized material.

[0029] The carbon-storing element comprises a barrier layer, which encapsulates the storage body. The term "encapsulate" is meant as fully enclosing the storage body so that the surface of the storage body is not in contact with the environment. The barrier layer has the function of protecting the surface as well as the bulk of the storage body of the carbon- storing element. The protection afforded by the barrier layer is, on one hand, protection against external factors, and in particular against oxidation by molecular oxygen such as atmospheric oxygen or oxygen that is dissolved in water and against the ingress of water or water vapor. On the other hand, the barrier layer is also meant to preserve conditions inside the carbon-storing element, i.e. in the storage body of the carbon-storing element, such as for example keeping a predetermined level of oxygen concentration and / or a predetermined level of humidity, in the storage body of the carbon-storing element, which may be advantageous in some embodiments. It is believed that the carbon-storing element according to the invention may be stored, if left undisturbed, for more than a century in underground vaults such as mine shafts or pits without release of more than 0.5 -1% of the carbon sequestered, in the carbon-storing element according to the invention.

[0030] The total carbon content (TC) of the storage body is of at least 10% by weight, preferably at least 40% by weight, more preferably at least 70% by weight, most preferably at least 90% by weight, based on the weight of the storage body.

[0031] The total organic carbon content (TOC) may be determined using known methods, such as for example by mass spectrometry analysis, low temperature oxygen plasma ashing or fine pulverization of samples. Various standardized methods exist to determine the total carbon content, the total organic or total inorganic carbon content. For example, the carbon content of the storage body may be provided via ASTM standard that exists for Peat (D 2974) and Coal (D 3174).

[0032] While the total carbon content (TC) may be determined with the above methods the total carbon content may be also derived from total organic carbon content and total inorganic carbon content.

[0033] TC = TIC + TOC (I) where TIC is the total inorganic carbon content, and where TOC is the total organic carbon content, and when measured according to DIN 15936:2012-11. While ideally the carbon content of the storage body should be as high as possible, it has been found that a storage body with a carbon content of 10% by weight, based on the weight of the storage body, can be useful in the carbon storing element.

[0034] However, in further preferred embodiments, the storage body has a carbon content of at least 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90% by weight based on the weight of the storage body and when measured according to DIN 15936:2012-11. In a preferred embodiment of the carbon-storing element according to the invention, the barrier layer has an oxygen transmission rate of less than 1 g rrr2 / 24h and preferably between 10'2g rrr2 / 24h and 1 g rrr2 / 24h and / or a water vapor transmission rate (WVTR) of less than 1 g rrr2 / 24h and preferably between 10'2g m’2 / 24h and 1 g nr2 / 24h. An oxygen transmission rate (OTR) of less than 1 g m’2 / 24h ensures that the ingress of oxygen into the storage body, across the barrier layer, can be kept to a minimum even over prolonged periods. Similarly, a water vapour transmission rate (WVTR) of less than 1 g m’2 / 24h ensures that the ingress of humidity into the storage body, across the barrier layer, is kept to a minimum. Ideally, the oxygen transmission rate (OTR) and / or a water vapor transmission rate (WVTR) are not measurable for the barrier layer, i.e. the barrier layer should be oxygen- an / or water vapour-proof.

[0035] In a preferred embodiment of the carbon-storing element according to the invention, the barrier layer is insoluble in aqueous solutions, such as briny water, saltwater, brackish water or freshwater at 25°C, 30°C, 40°C, 50°C, 60°C or higher. Thus, stated alternatively, the barrier layer should be waterproof. In particular, the carbon-storing element according to the invention may be temporarily stored in the open after production, which includes exposure to rain and snow, freeze / thaw cycles, in which case a barrier layer that is insoluble in aqueous solutions can be advantageous. Likewise, when the carbon-storing element according to the invention is used in its final storage location, such as for example in mining pits or mine shafts, or in the subbase layer of a surface transport structure, conditions can be humid or wet, with temperatures range from 0°C to 50°C and more, the water-insoluble barrier layer protects the storage body of the carbon-storing element against water ingress and swelling, which can lead to the breaking of the barrier layer from expansion of the storage body. It is thus an advantage of the present invention to prevent the elution (leaching) of noxious substances from the at least partially carbonized material of the storage body of the carbon-storing element in humid, wet or even submerged environments, to protect groundwater supplies.

[0036] In a preferred embodiment of the carbon-storing element according to the invention, the barrier layer is resistant against photodegradation, for example via UV, and comprises a radiation stabilizer agent such as for example a benzophenone or a benzotriazole derivative. When used as a polymer additive in the barrier layer, the radiation stabilizer agent may be used in a concentration of 0.1 to 1 % by weight, based on the weight of the barrier layer. In a preferred embodiment of the carbon-storing element according to the invention, the storage body is formed of a storage body composition comprising an at least partially carbonized material such as carbonized material of biological origin, optionally in combination with a binder material. While the at least partially carbonized material can be sourced from any carbonaceous material, such as organic refuse including synthetic polymer materials, cardboard, paper, sewage sludge, food waste, or manure, the at least partially carbonized material is preferably at least partially carbonized biomass. The biomass may be any available biomass such as plant or animal matter, and more preferably is plant matter such as wood, for example in the form of softwood chips, hardwood chips, wood pellets, timber harvesting residues, tree branches, tree stumps, leaves, bark, or sawdust, or is plant matter from crops such as corn, corn stover, wheat, wheat straw, rice, rice straw, sugarcane, sugarcane bagasse, sugarcane straw, energy cane, sugar beets, sugar beet pulp, sunflowers, sorghum, canola, algae, miscanthus, alfalfa, switchgrass, fruits, fruit shells, fruit stalks, fruit peels, fruit pits, vegetables, vegetable shells, vegetable stalks, vegetable peels, vegetable pits, grape pumice, almond shells, pecan shells, coconut shells, coffee grounds or grass pellets, hay pellets.

[0037] In a preferred embodiment of the carbon-storing element according to the invention, the at least partially carbonized material provides for at least 50%, 60%, 70%, 80%, 85% and preferably at least 90% of the carbon content of the storage body.

[0038] In a preferred embodiment of the carbon-storing element according to the invention, the storage body comprises an at least partially carbonized material in combination with a binder material, preferably a liquid binder material. However, in some embodiments, the storage body may be free of binder material, or at least be free of a solid binder material. In a preferred embodiment of the carbon-storing element according to the invention, the storage body may be a free-flowing powder, a slurry, a putty, a mastic or paste.

[0039] In a preferred embodiment of the carbon-storing element according to the invention, the at least partially carbonized material and / or the storage body is in the form of a powder. When the carbonized material and / or the storage body is in the form of a powder, the carbon- storing element is deformable, similar to a rubber balloon filled with sand, which in some embodiments and in particular when the carbon-storing element is used as the subbase layer of a surface transport structure or as a geomembrane layer, since it allows a layer of loose carbon-storing elements to be packed, for example by applying pressure and / or vibrations into a more compact layer. Thus, the carbonized material and / or the storage body is in the form of a powder, the granulometry of the powder is between 0.0001 mm to 5 mm, and more preferably is between 0.1 mm to 1 mm.

[0040] In a preferred embodiment of the carbon-storing element according to the invention, the at the least partially carbonized material is hydrochar or biochar, and preferably is hydrochar. While biochar is produced via pyrolysis of a carbonaceous material, hydrochar is produced via hydrothermal carbonization (HTC) of a carbonaceous material. Due to the dry nature of the pyrolytic process, the biochar is obtained in a dry state. In that dry state, the biochar is quite reactive to ambient oxygen and it is therefore preferred to provide the least partially carbonized material as hydrochar, which due to the incomplete elimination of water can yield an at least partially carbonized material that is moist or can even be in the form of a slurry. In its moist form or slurry form, the hydrocar has a low reactivity to ambient oxygen. If biochar is used, it may be humidified to the appropriate degree of moisture. When hydrochar is used, the hydrochar is preferably mechanically dewatered to decrease the energy consumption.

[0041] In a preferred embodiment of the carbon-storing element according to the invention, the at the least partially carbonized material is hydrochar and has a carbon content of at least 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90% by weight, based on the weight of the storage body and when measured according to DIN 15936:2012-11.

[0042] In a preferred embodiment of the carbon-storing element according to the invention, the at the least partially carbonized material is biochar and has a carbon content of at least 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90% by weight, based on the weight of the storage body and when measured according to DIN 15936:2012-11.

[0043] In a preferred embodiment of the carbon-storing element according to the invention, the at least partially carbonized material and / or storage body and / or storage body composition has a moisture of about 15 %, or between 10 and 40 % by weight with respect to carbonized material and / or storage body and / or storage body composition, respectively.

[0044] In a preferred embodiment of the carbon-storing element according to the invention, the storage body and / or storage body composition further comprises a humidifying liquid, which may be water or an aqueous solution of a humidifying agent such as a polyol, preferably ethylene glycol, propylene glycol, glycerol, butanediols, butanetriols, erythritol, xylitol, sorbitol, or combinations thereof. The humidifying liquid meant to tune the moisture of the storage body and / or storage body composition.

[0045] In a preferred embodiment of the carbon-storing element according to the invention, the storage body composition or storage body may have a moisture content of about 1 to 40%, by weight, preferably of from 1 to 20% by weight or of from 20 to 40% by weight, based on the total weight of the storage body composition or of the storage body. Especially when the moisture content is high, the storage body composition and / or the storage body will be plastic, or deformable. When hydrochar is used, the moisture level can be adjusted directly by adjusting the extent of the dewatering during hydrochar production.

[0046] In a preferred embodiment of the carbon-storing element according to the invention, the storage body composition and / or the storage body will be plastic, or deformable. Especially, when the barrier layer is made from an elastic or plastic material, the carbon-storing element becomes deformable either plastically or elastically, which may be particularly useful when the carbon-storing element is used in landfill, road construction and other applications where the carbon-storing elements are compacted either actively via external mechanical pressure such as steamrolling or by virtue of passive pressure such as the weight of the carbon-storing element.

[0047] In a preferred embodiment of the carbon-storing element according to the invention, the storage body further comprises a biogenic mineral such as a carbonate or a silicate. The biogenic mineral may for example be shells of marine or freshwater bivalves or diatomaceous earth. Another biogenic mineral material may be eggshells, which may be sourced from egg production factories. An advantage of adding biogenic minerals is that it is possible to increase the density of the storage body composition or of the storage body, and by extension, of the carbon storing element.

[0048] In a preferred embodiment of the carbon-storing element according to the invention, the barrier layer is a coating. A coating may be formed by coating the storage body with a coating composition, which may be liquid or solid. In the case where the coating composition is a liquid, the storage body may be coated with the coating composition by spray coating, dipping, immersing, drum coating, curtain coating or any other suitable coating method available. Subsequently, the liquid coating composition on the storage body may be dried to form the barrier layer. In the case where the coating composition is a solid, the storage body may be coated with the coating composition, for example in powder form, and the coating composition may subsequently be fused into a barrier layer via heat or radiation.

[0049] In a preferred embodiment of the carbon-storing element according to the invention, the barrier layer is a sealed packaging such as a wrapper or a sachet. For example, the storage body can be placed into a packaging film and the packaging film can be sealed such as to enclose the storage body in the thus formed sealed package, similarly to a sugar stick. Preferably, the seals may be formed via heat-sealing or vibration sealing. In a preferred embodiment of the carbon-storing element according to the invention, the barrier layer is formed from a multilayer packaging film comprising a barrier film layer and a sealing layer. When a packaging film is used, the packaging film preferably has an oxygen transmission rate of between 10'2and 1 g rrr2 / 24h and / or a water vapor transmission rate (WVTR) of between 10'1and 1 g rrr2 / 24h.

[0050] In a preferred embodiment of the carbon-storing element according to the invention, the storage body further comprises an oxygen scavenger, preferably sodium hydrogen carbonate, ascorbic acid, iron or ferrous carbonate, such as iron powder or granules, which may be used in combination with a metal halide such as NaCI. The oxygen scavenger has a higher reactivity to oxygen than the other materials of the storage body and reacts with oxygen to reduce the concentration of oxygen in the storage body. In a preferred embodiment of the carbon-storing element according to the invention, the oxygen scavenger, is in the form of powder or granules that can be blended with the materials of the storage body, in particular with the at least partially carbonized material.

[0051] In a preferred embodiment of the carbon-storing element according to the invention, the storage body further has a free oxygen content of less than 2%, which is lower than the 20.9% oxygen found in ambient air.), when measured with industrial residual oxygen analyzer . This may be a result of the oxygen scavenger or when the storage body is free of added oxygen scavenger, the result of conditions during the manufacture of the carbon- storing element. In fact, the carbon-storing element may be manufactured in a protective atmosphere to avoid the inclusion of oxygen in the carbon-storing element.

[0052] In a preferred embodiment of the carbon-storing element according to the invention, the carbon-storing element is capable of being deformed by mechanical force. In order for the carbon-storing element to deform, the barrier layer as well as the storage body must be capable of being deformed by mechanical force. While the capability of being deformed can be achieved in some embodiments by a storage body in the form of a free-flowing powder, a slurry, a putty, a mastic or paste, the barrier layer has the capability of being deformed when the barrier layer has a Young's modulus of from 2 to 10'4GPa or when it is made from an elastic material such as a elastomeric rubber.

[0053] In a preferred embodiment of the carbon-storing element according to the invention, the barrier layer is made from an elastically deformable material.

[0054] In a preferred embodiment of the carbon-storing element according to the invention, the barrier layer may be formed of a synthetic organic polymer such as polyolefins, polyesters, polyurethanes, polycarbonates, polyether ketones, polyamides and so on. Preferably, the synthetic organic polymer is a polyolefin, which in contrast to condensation polymers are less vulnerable against hydrolysis. If a binder material is used in the storage body of the carbon-storing element to bind the at least partially carbonized material of the storage body, the barrier layer is preferably formed of different material than the binder material.

[0055] In a preferred embodiment of the carbon-storing element according to the invention, the barrier layer may be formed from a synthetic rubber material such as silicone rubber or acrylic rubber, ethylene propylene rubber, ethylene propylene diene rubber, or thermoplastic rubbers and such.

[0056] In a preferred embodiment of the carbon-storing element according to the invention, the storage body of the carbon-storing element, or the storage body composition, may comprise a binder material. The binder material serves the purpose of binding the at least partially carbonized material, which may be dispersed in the binder material. The binder material may be any material and may solidify to provide a hard storage body or a storage that is capable of being deformed. For example, a binder material may be a hydraulic binder such as cement, in which case the storage body will be hard once the cement is fully hydrated, or may be a elastically deformable binder, in which case the storage body will be deformable when pressure is applied.

[0057] In a preferred embodiment of the carbon-storing element according to the invention, the barrier layer may be formed of a synthetic organic polymer that is a self-healing polymer such as ionomers and vitrimers. In a preferred embodiment of the carbon-storing element according to the invention, the weight of the barrier layer is between 0.001 % and 25 % by weight, preferably between 0.1 % and 5 % by weight, more preferably between 0.1 % and 1 % by weight and / or the weight of the storage body is 75 and 99.999 % by weight, preferably 95 and 99.9 % by weight, more preferably 99 and 99.9 % by weight based on the total weight of the carbon-storing element.

[0058] In a preferred embodiment of the carbon-storing element according to the invention, the barrier layer is made of an inorganic material, such as metal or a mineral such as a silicate.

[0059] In a preferred embodiment of the carbon-storing element according to the invention, the storage body is extruded, and is preferably a pellet or granule. Roughly spherical or ellipsoid shapes are preferred, as they reduce the surface to volume ratio and because coating the pellet or granule with a barrier layer can be more easily achieved. In some embodiments, the cross-section of the extruded storage body may be round, elliptic, polygonal such as square, hexagonal or trigonal. Furthermore, pelletization or granulation are suitable for mass production since extruders are well-known in the field of making coal.

[0060] In a preferred embodiment of the carbon-storing element according to the invention, the storage body may be formed via a pelletizer, into which the storage body composition is fed. Exemplary pelletizers are rotary drum pelletizer or a disc pelletizer (or pan granulator).

[0061] In a preferred embodiment of the carbon-storing element according to the invention, the storage body or the storage body composition may comprise tracer material. While rupture of the barrier layer is unlikely, it may nonetheless happen when a large number of storage elements used, such as in geomembranes or carbon capture vaults. In order to be able to detect leakages, the tracer material leaking from the storage body or the storage body composition can be detected in effluents from the site of leakage such as for example runoff water. Ideally, the tracer material is not a hazardous substance. For example, a dye or a metal ion could be used, which may be detected via chromatography, mass spectrometry or elemental analysis.

[0062] In a preferred embodiment of the carbon-storing element according to the invention, the storage body is compression formed, and is preferably a pyramid, tetrahedron, cube, parallelepiped, cylinder or and is more preferably a building block such as for example a building block comprising protrusions and depressions that can interlock when a building block is placed next to, or above, another building block.

[0063] In a preferred embodiment of the carbon-storing element according to the invention, the storage body is the carbon-storing element has a density of more than 103kg / m3. When the storage body is the carbon-storing element has a density of more than 103kg / m3, the carbon storing element remains in place when it is stored in environments that are prone to flooding or immersion, such as for example abandoned pit mines or mine shafts or to infiltration of water such as in geomembranes.

[0064] In a preferred embodiment of the carbon-storing element according to the invention, the storage body has a volume of about 0.5 cm3to 5 cm3, or from 5 cm3to 1000 cm3or from 1000 cm3to 1 m3. When the carbon-storing element is used in applications where it replaces aggregate such as sand or clay, the storage body has preferably a volume of about 0.5 cm3to 5 cm3. When the carbon-storing element is used in applications where it the sole that is more akin to landfilling, the storage body has preferably a volume of about 1000 cm3to 1 m3.

[0065] In a preferred embodiment of the carbon-storing element according to the invention, the carbon-storing element is free of edges or has a rounded edges. When the carbon-storing element is free of edges or has a rounded edges, the barrier layer is less exposed to friction and impinging and the probability of damage to the barrier layer can be reduced.

[0066] In a preferred embodiment of the carbon-storing element according to the invention, the storage body further comprises a non-flammable material, such as clay or sand or Calcium carbonate, preferably in an amount of up to 80% weight percent, more preferably of from 20 to 80%, based on the weight of the storage body.

[0067] In a preferred embodiment of the carbon-storing element according to the invention, the storage body the storage body has a compression strength of 300 to 1000 KPa.

[0068] In a preferred embodiment of the carbon-storing element according to the invention, the barrier layer has a thickness of between 0.01 and 2 mm, preferably between 0.1 and 2mm, more preferably between 1 mm to 2 mm.

[0069] In a preferred embodiment of the carbon-storing element according to the invention, the bulk density / tapped density of the carbon-storing element is between 700 kg / m3and 1000 kg / m3or between 100 kg / m3to 1200. kg / m3

[0070] It is a further objective of the present invention to provide a process to produce a carbon- storing element according to the first object of the invention, wherein the process includes the steps of:

[0071] - forming a storage body from a storage body composition comprising at least partially carbonized material such as biochar and / or hydrochar,

[0072] - forming a barrier layer on the storage body to encapsulate the storage body in said barrier layer.

[0073] In a preferred embodiment of the process to produce a carbon-storing element according to the first object of the invention, the storage body composition is formed into a storage body via compaction or extrusion.

[0074] In a preferred embodiment of the process to produce a carbon-storing element according to the first object of the invention, the barrier layer is formed on the storage body by coating the storage body with a coating composition, which may be liquid or solid. Suitable methods to apply a liquid coating composition may be for example spray-coating, dipping, immersing, curtain coating or drum coating. In particular, fluidized bed coating of the storage body. In a fluidized bed coating, the coating composition is atomized a passed through the particles to be coated.

[0075] It is a yet further objective of the present invention to provide a geomembrane, such as a landfill liner layer, comprising a plurality of compacted carbon-storing elements according to the first object of the invention, and preferably wherein the geomembrane further comprises a clay such as bentonite clay. In particular, the clay is preferably located in the interstices between the carbon-storing elements. In a preferred embodiment, the landfill layer may have a thickness of between 10 cm and 10 m, preferably from 50 cm to 5 m, in which case the landfill layer is generally impermeable to water and protects groundwater from leaching that occurs in the landfill material proper. It is a yet further objective of the present invention to provide a bulk aggregate for construction, such as for surface transport structure construction, comprising a plurality of loose carbon-storing elements according to the first object of the invention, preferably wherein the carbon-storing elements are in pellet or granule form, and optionally the bulk aggregate further comprises a mineral construction aggregate such as gravel, sand or clay. The bulk aggregate may comprise of from about 5 % by weight to about 95% by weight of carbon-storing elements according to the first object of the invention. In a preferred embodiment, the landfill layer may have a thickness of between 10 cm and 10 m, preferably from 50 cm to 5 m, in which case the landfill layer is generally impermeable to water due to self-compaction.

[0076] Alternatively, the landfill layer may be compacted (i.e. densified ) actively by methods known in the art of construction, such as for example by passing with a compactor vehicle.

[0077] It is a yet further objective of the present invention to provide a use of the carbon-storing element according to the first object of the invention, as a loose construction aggregate in surface transport system construction, in particular in a subbase layer of a surface transport structure. Aggregate cost, in particular fueled by scarcity of gravel or sand, is rising and the carbon-storing element according to the first object of the invention, when provided in the right granulometry, can subsitute a part or all of the aggregate in surface transport system construction such as roads while at the same safely sequestering carbon from release into the atmosphere.

[0078] It is a yet further objective of the present invention to provide a use of the carbon-storing element according to the first object of the invention, as a landfill material, in particular as carbon-storage landfill material. While biochar and hydrochar cannot be introduced into landfills because of the total organic carbon (TOC) content (and therefore, also the total carbon content) at 400°C is too elevated and not permitted according to regulations, the barrier layer of the carbon-storing element according to the first object of the invention makes landfilling of either biochar or hydrochar possible, because the carbon bound in the storage body is protected from oxidation on one hand and protected against leaching on the other hand by the barrier layer.

[0079] It is a yet further objective of the present invention to provide a use of the carbon-storing element according to the first object of the invention, as a building element in masonry, preferably as a brick, preferably wherein the building element consists of agglomerated carbon-storing elements.

[0080] It is a yet further objective of the present invention to provide a use of the carbon-storing element according to the first object of the invention, in a geomembrane layer, preferably in combination with a geotextile layer.

[0081] LIST OF REFERENCE SIGNS

[0082] 0 carbon-storing element

[0083] 1 storage body 2 barrier layer

[0084] 3 mineral construction aggregate

Claims

CLAIMS1. A carbon-storing element (0) comprising a storage body (1) and a barrier layer (2), wherein the storage body (1) is formed of a storage body composition comprising an at least partially carbonized material, optionally in combination with a binder material, characterized in that the barrier layer encapsulates the storage body.

2. The carbon-storing element according to any preceding claim, wherein the barrier layer is waterproof.

3. The carbon-storing element according to any preceding claim, wherein wherein the storage body has a total carbon content (TC) of at least 10% by weight, based on the weight of the storage body.

4. The carbon-storing element according to any preceding claim, wherein the least partially carbonized material is in the form of a powder, preferably having a granulometry of between 0.0001 mm to 5 mm.

5. The carbon-storing element according to any preceding claim, wherein the least partially carbonized material is hydrochar or biochar.

6. The carbon-storing element according to any preceding claim, wherein the storage body and / or storage body composition further comprises a biogenic mineral such as a carbonate or a silicate, and / or a mineral filler material such as sand, gravel or clay.

7. The carbon-storing element according to any preceding claim, wherein the barrier layer is a coating.

8. The carbon-storing element according to any preceding claim, wherein the barrier layer is a packaging.

9. The carbon-storing element according to any preceding claim, wherein the storage body and / or storage body composition further comprises a humidifying liquid.

10. The carbon-storing element according to any preceding claim, wherein the storage body and / or storage body composition further comprises an oxygen scavenger, such as iron powder.11 . The carbon-storing element according to any preceding claim, wherein the storage body has a free oxygen content of less than 2%.

12. The carbon-storing element according to any preceding claim, wherein the carbon-storing element is deformable and is preferably elastically orplastically deformable, in particular via mechanical pressure.

13. The carbon-storing element according to any preceding claim, wherein the weight of the barrier layer is between 0.001 % and 25 % by weight, preferably between 0.1 % and 5 % by weight, more preferably between 0.1 % and 1 % by weight, based on the total weight of the carbon-storing element, and / or the weight of the storage body is 75 and 99.999 % by weight, preferably 95 and 99.9 % by weight, more preferably 99 and 99.9 % by weight based on the total weight of the carbon-storing element.

14. The carbon-storing element according to any preceding claim, wherein the barrier layer is made of a synthetic organic polymer, preferably a self- healing polymer.

15. The carbon-storing element according to any preceding claim, wherein the barrier layer is made of an inorganic material, such as metal or a mineral such as a silicate.

16. The carbon-storing element according to any preceding claim, wherein the storage body is extruded, and is preferably a pellet or granule.

17. The carbon-storing element according to any preceding claim, wherein the storage body is compression formed, and is preferably a building block.

18. The carbon-storing element according to any preceding claim, wherein the carbon-storing element has a density of more than 103kg / m3.

19. The carbon-storing element according to any preceding claim, wherein the carbon-storing element is free of edges or has a rounded edges.

20. The carbon-storing element according to any preceding claim, wherein the storage body further comprises clay or sand or calcium carbonate, preferably in an amount of preferably in an amount of up to 80% weight percent, based on the weight of the storage body.,21. The carbon-storing element according to any preceding claim, wherein the storage body has a compression strength of 300 to 1000 kPa.

22. The carbon-storing element according to any preceding claim, wherein the barrier layer has a thickness of 0.01 and 2 mm.

23. The carbon-storing element according to any preceding claim, wherein the storage body has a volume of about 1 cm3to 1000 cm3or to 1 m3.

24. The carbon-storing element according to any preceding claim, wherein the storage body has a moisture content of about 0 to 40%.

25. The carbon-storing element according to any preceding claim, wherein the bulk density / tapped density of the carbon-storing element 700 kg / m3to1200. kg / m3.

26. The carbon-storing element according to any preceding claim, wherein the total organic content of the wherein the storage body is of at least 50% by weight, based on the weight of the storage body.

27. A process to produce a carbon-storing element according to any one of the preceding claims, wherein the process includes the steps of- forming a storage body from a storage body composition comprising an at least partially carbonized material, such as biochar and / or hydrochar, into a storage body,- forming a barrier layer on the storage body to encapsulate the storage body in said barrier layer.

28. The process to produce a carbon-storing element according to claim 27, wherein the storage body composition is formed into a storage body via compaction or extrusion.

29. The process to produce a carbon-storing element according to claim 27 or 28, wherein the barrier layer is applied to the storage body by coating.

30. A geomembrane, such as a landfill liner layer, comprising a plurality of carbon-storing elements according to any one of claims 1 to 26, and preferably wherein the geomembrane further comprises a clay such as bentonite clay.

31. A bulk aggregate for construction comprising a plurality of carbon-storing elements according to any one of claims 1 to 26, preferably in pellet or granule form, and optionally comprising a mineral construction aggregate such as sand or clay.

32. Use of the carbon-storing element according to any one of claims 1 to 26 as a loose construction aggregate in surface transport system construction, in particular in a subbase layer of a surface transport structure.

33. Use of the carbon-storing element according to any one of claimf 1 to 26 as a landfill material, in particular as carbon-storage landfill material.

34. Use of the carbon-storing element according to any one of claims 1 to 26 as a building element in masonry, preferably as a brick, preferably wherein the building element consists of agglomerated carbon-storing elements.

35. Use of the carbon-storing element according to any one of claims 1 to 26 in a geomembrane layer.

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