Method and device for creating a construction material on the basis of solid carbon and a binder

Abstract

The invention relates to a system for producing a carbon construction material which is structurally similar to concrete, the construction material preferably consisting of the components structural material, filling material and binding material. Both the structural material and the filling material are produced from solid carbon resulting from methane pyrolysis or CO2 reduction. If biomethane is used as the input for the methane pyrolysis, a CO2-negative construction material is made, which contributes to the removal of the natural gas CO2 from the atmosphere.

Description

[0001] Method and device for producing a building material based on solid carbon and a binder

[0002] To manage climate change, it is advisable to limit the emission of the climate-relevant trace gas CO2 into the atmosphere or even to remove CO2 from the atmosphere. In this context, it is of great importance that the most important industrial mass flows are decarbonized. One of the most mass-effective industrial building materials is cement, which is mixed with sand and water and used to form concrete. Global cement production generates a carbon footprint in the gigatons range per year and is therefore one of the most important sources of carbon dioxide emissions. Decarbonizing the traditional cement production process is difficult because CO2 is released during the firing of the calcareous base material. It is therefore desirable to replace the cement / concrete system with alternative carbon dioxide-neutral or even carbon dioxide-negative building materials.

[0003] It is certainly attractive to mimic the structure of concrete. Concrete consists of a mixture of sand, cement, and water. The sand portion represents the structural component that can absorb compressive and shear forces. To achieve this, however, the sand grains used must have sharp edges in order to wedge themselves against each other in the cement matrix. Rounded sand grains, such as those found in desert sand dunes, are not suitable. When water is added, the cement sets via the pozzolanic reaction, which cross-links the system three-dimensionally and thus stabilizes it. This means it can also absorb tensile forces to a certain extent. The concrete system can be used extremely flexibly – from the casting of building components such as walls or ceilings on site to the production of prefabricated building elements and, more recently, large-scale 3D printing directly on site.

[0004] If this traditional concrete system based on mineral cement and sand is to be replaced in the interest of climate protection, materials must be used that can be supplied on a similar scale, namely in the range of 1-5 gigatons per year. Existing alternative systems such as timber construction cannot achieve such a large-scale substitution due to the lower mass availability of timber.

[0005] The oil and gas industry is also making significant efforts to decarbonize its products. Natural gas—chemically known as methane—can, for example, be converted into the climate-neutral raw material and energy carrier hydrogen. Two reactions can be used for this conversion:

[0006] • Steam reforming produces (climate-damaging) CO2 in addition to (blue) hydrogen, which would have to be captured and stored / used (CCS or CCU).

[0007] • An alternative process for converting methane to (turquoise) hydrogen is methane pyrolysis. Methane pyrolysis does not produce climate-damaging CO2; instead, solid carbon is produced.

[0008] Solid carbon is a non-toxic, stable solid. Due to the high production volumes of natural gas, the widespread use of methane pyrolysis can achieve a mass availability of solid carbon comparable to that of traditional cement.

[0009] Waste management treats organic waste, which also represents a mass flow comparable to cement. Currently, organic waste is usually thermally treated, converting its main component, carbon, into climate-damaging CO2. Since waste usually originates from biogenic sources, the carbon it contains is produced from atmospheric CO2 through photosynthesis, which means that waste incineration can at least be classified as largely CO2-neutral. Newer waste treatment processes such as anaerobic digestion produce biogas, which, after the CO2 is separated, can be converted into biomethane, which can replace natural gas. Experimental processes such as waste hydrogenation (see: PCT-DE2019000158) could convert almost all biogenic waste into methane, thus generating a methane mass flow comparable to natural gas.Biomethane / RNG (renewable natural gas) could thus replace natural gas as the raw material for methane pyrolysis when fossil fuels are phased out. Compared to natural gas, biomethane / RNG has a negative CO2 effect and can therefore play an important role in the desired removal of CO2 from the atmosphere.

[0010] Methane pyrolysis therefore has the potential to become a key technology for decarbonization, particularly in the oil and gas industry and waste management. In light of climate change mitigation, it is therefore attractive to use the resulting solid carbon, for example, in the production of building materials. Substituting traditional, highly CO2-emitting cement with (carbon-neutral or even carbon-negative) solid carbon building materials could make an important contribution to decarbonizing the construction industry. In the described approach, three important industries could be decarbonized step by step using a single integrated process combination – promising significant overall cost advantages.

[0011] Efforts have therefore already been made to develop building materials made from solid carbon. CarbonAir (see Ref. 2), for example, creates a cement substitute by using solid carbon as a structural material and an aqueous organic binder based on a lignin resin, which cures upon application of heat and crosslinks the building material three-dimensionally.

[0012] Solid carbon from methane pyrolysis is a very pure carbon, as the only feedstock used in methane pyrolysis is methane. It is produced in a consistent quality and can therefore serve as the basis for a reproducible process for producing a quality-assured building material. Consistent solid carbon quality is crucial for standardized building material quality. Solid carbon obtained from methane pyrolysis differs significantly from carbon from biomass pyrolysis, whose quality varies greatly depending on the heterogeneous feedstock.

[0013] It was shown that the physicochemical structure of solid carbon is crucial for its suitability as a building material and the design of the building material production process. Table 1 lists the three currently relevant methane pyrolysis processes and characterizes the properties of the final solid carbon product with regard to particle size, particle shape, and particle stability.

[0014] Table 1: Current methane pyrolysis processes and properties of the final product, solid carbon, with regard to particle size, particle shape, and particle stability. To create a system structurally similar to concrete using solid carbon, two particle sizes are advantageous: large particles that take on the pressure-absorbing function of the sand in the concrete, and small particles that, together with the added binder, can fill the gaps between the large particles and create three-dimensional cross-linking that can absorb tensile forces to a certain extent. Table 1 shows that the plasma process produces small, sub-mm particles, while the moving bed reactor produces large particles with a particle size of 2-5 mm. In between lies the molten bed reactor, whose medium-sized particles have a slag-like consistency and low particle stability.

[0015] Considering the particle size, the solid carbon used in plasma and molten-bed reactors could serve as a filler material, with the limitation for plasma reactors being that the particles have an unfavorable round shape. The solid carbon used in moving-bed reactors could serve as a structural material due to its particle size. However, the round, spherical shape prevents the particles from interlocking, thus preventing the high required pressure and shear force absorption. Therefore, all three solid carbon varieties are ruled out as concrete substitutes.

[0016] In contrast to this initial situation, the present invention creates a three-component system comparable to concrete from solid carbon from the moving bed reactor and a binder, which is capable of absorbing high compressive and shear forces.

[0017] Description of the invention

[0018] The three-component system according to the invention consists of:

[0019] • Component 1: Structural material: angular particles with a grain size of 1-5 mm, preferably 1-2 mm

[0020] • Component 2: Filling material: particles with a grain size of <1 mm • Component 3: Binding material: organic or inorganic binder With the process according to the invention, components 1 and 2 are produced from the same starting material: solid carbon from methane pyrolysis using the moving bed process.

[0021] The overall process according to the invention consists of the following steps:

[0022] 1. Shattering: The input material spherical solid carbon is shattered into several angular splinters and fine material

[0023] 2. Separation: The debris is separated into two fractions: a. Coarse fraction to form component 1 / structural material b. Fine fraction to form component 2 / filling material

[0024] 3. Surface treatment: Optional step to functionalize the surface of one or both fractions for the respective organic or inorganic binder.

[0025] 4. Mixing: Components 1 (structural material), 2 (filler material), and 3 (binding material) are preferably prepared separately for the production of components. In another preferred variant, components 2 (filler material) and 3 (binding material) are provided premixed.

[0026] The three-component system is used to manufacture components using the following work steps:

[0027] 1. Molding: Casting, injection molding, 3D printing of structures on site or of prefabricated components, also using reinforcement (steel, carbon fiber)

[0028] 2. Curing of the manufactured structures or components.

[0029] An obvious approach to creating the structural material is to grind the input material, solid carbon, to eliminate the unfavorable round spherical shape. Unfortunately, this is not possible because the repeated contact of the solid carbon spheroids with the grinding tool results in fragments that are too small and the edges of these fragments become unfavorably rounded, preventing them from wedging together in the workpiece.

[0030] The inventive method utilizes a crusher according to the invention for the simultaneous production of structural material and filler material in combination with a modified sorter known from grain handling in a device chain. With this previously unknown equipment and unobvious combination, the solid carbon spheroids can be crushed to large particle sizes comparable to the size of the spheroids themselves, and to particles whose edges are not rounded.

[0031] In the arrangement according to the invention, the solid carbon feedstock is fed into a crusher derived from the impact mill, which, surprisingly, shatters the spheroids into splinters and fine material with a single impact. The splinters are discharged from the crusher, but usually still contain a larger number of unshattered spheroids.

[0032] According to the invention, these are then identified and separated by a sorter based on their spherical shape. They leave the sorter and are returned to the crusher. Angular particles with a grain size of 0.5-5 mm, preferably 1-3 mm, also leave the sorter as a product. This product of the crusher / modified sorter device chain can be used directly as structural material (component 1). Fine material < 1 mm created in the crusher is separated using a sifter or sieve and used as filler material (component 2).

[0033] Traditional impact mills consist of a rapidly rotating plate-type impact mill and a grinding track arranged around the impact mill, e.g., a trapezoidal fluted grinding track or, alternatively, a pin-type impact mill. In a state-of-the-art grinding process, comminution occurs through constant impact contact of the material to be ground with the impact mill and the grinding track, resulting in a reciprocating motion between the impact mill and the grinding track. The material to be ground is conveyed into the crusher in a process air stream, swirled there, and then discharged from the crusher. The process air is then filtered to remove dust particles.

[0034] In contrast to this state of the art, the fragmentation of the spheroids WITHOUT rounding the edges of the fragments is achieved by reducing the number of contacts with the impact mechanism in the fragmentizer, preferably to 1 impact contact number. After this first impact has achieved fragmentation, the process material must leave the crusher in the air stream without repeated rebounding between the impact mechanism and the grinding track. For this purpose, the trapezoidal riffle grinding track is removed. At a further distance, a coarse-grained sieve is used instead, preferably a long slot sieve, with a hole size equal to or larger than the average diameter of the solid carbon spheroids, preferably with a width of the long slots of 2-5 mm. Another preferred design is the complete removal of the grinding track using a collecting tray located comparatively far away.

[0035] The cost of fragmenting the solid carbon spheroids while preserving the fracture edges is that, when the material passes through the fragmenter according to the invention without rebound from the grinding track, only a portion of the added spherical particles are fragmented. However, due to their rounded shape, the unfragmented spheroids must not be contained in the product and must therefore be separated. This is not possible using state-of-the-art sieving or sifting, as spheroids and fragments differ only relatively slightly in terms of both grain size and grain weight. Surprisingly, this problem can be solved by modifying a device used in grain processing to separate weed seeds from grain kernels: the sorter (see Ref. 5).

[0036] Sorters are operated as drum sorters or screw sorters. In a drum sorter, a horizontal drum rotates, which has bowls on the inside wall. The input material is grain contaminated with weed seeds, which is fed into the bottom of the rotating drum. The bowls are designed so that the grain kernels fit easily into them. The rotation lifts the grain kernels rolled into the bowls and fall into a trough at a certain height. Larger or smaller weed seeds fall out further down or higher up and then also fall into troughs there, where they are separated. In a screw sorter, the kernels slide passively down a vertically mounted auger, with separation occurring because round weed seeds roll more easily to the outside of the spiral and are separated there from the grain running inside.The inventive sorter similarly picks up the rounded solid carbon spheroids using adapted cup recesses in the drum, thus separating them from the angular splinters. A screw sorter can also be used, in which the splinters slide downwards along the inner track, while the round spheroids roll easily onto the outer track.

[0037] The combination of the inventive shattering device with the modified sorting device thus enables the simultaneous production of an angular structural material and a fine fraction usable as filler material. A particularly advantageous design is one in which the top-fed shattering device is combined with a classifier and a screw sorting device at the bottom outlet. This allows the structural material to be taken over at the outlet of the screw sorting device at the level of the downstream processes, while the rejected spheroids are blown back to the top feed.

[0038] Detailed description of the invention and drawings

[0039] The invention is illustrated in drawings and is explained in more detail using exemplary embodiments.

[0040] Figure 1 shows the basic process according to the invention. Solid carbon particles [1] serve as the input material for the fragmentation process. [2] schematically shows the fragmentation pattern of a solid carbon particle according to the invention. It can be seen that, in addition to the fragmentation fragments produced, fine material is also generated in the fragmentation process. Fractions can preferably be separated, resulting in filler material [3] as the fine fraction of the fragmentation process and structural material [4] as the coarse fraction of the fragmentation process. The entire fragmentation material can also be used without separation.

[0041] Both materials, together with the binding material / binder [5], serve as the input material for the curing process for component production. Figure 2 shows the size ratio using an example solid carbon particle.

[0042] It has been shown that the inventive fragments, which represent the structural material to be produced, exhibit a linear expansion of up to the linear expansion of the starting material. This is in stark contrast to conventional grinding or crushing curtains, in which the ground material usually exhibits a linear expansion of 1 / 10 to 1 / 100 of the starting material. After adding the binding material, a blended solid carbon concrete is produced for the setting reaction.

[0043] Fig. 3 shows the distribution of the two materials in the mixed solid carbon concrete of the component or casting to be produced. The structural material, as the coarse fraction of the fragmentation process [4], forms a structural skeleton supported and tilted by the edges, which can absorb high compressive forces and withstand shear forces. It is encased in the mixture [7] of filler material [3] and binding material [5]. This inventive method of filling the gaps of the structural skeleton creates a high binding force that can easily absorb tensile forces.

[0044] Fig. 7 shows the crusher according to the invention in two versions (center and right) compared to an impact mill (left). In an impact mill, the material to be ground is accelerated in a grinding zone and crushed by repeated back and forth rebounding between the rotor tool / beater mechanism and the grinding track arranged around it. However, this leads to unfavorable length ratios of the material to be ground. The crusher according to the invention is shown in Fig. 7 center and right. The crusher does not have a grinding track but only the rotational axis

[0025] on which the crushing tools

[0026] are attached. Pin discs, plate beaters, pendulum beaters, or impact discs can be used as crushing tools. In a preferred variant, a remote coarse-hole sieve is used instead of the grinding track.It is preferably mounted at a distance of >2x the projection of the fragmentation tools and particularly preferably has a round or elongated hole with hole widths of >0.8x the average diameter of the solid carbon particles to be treated.

[0045] In another preferred variant, the removed coarse-hole screen is omitted and a remote collecting tray is used. The distance of the collecting tray is particularly preferably >3x the projection of the crushing tools. The crushed coarse material is continuously removed from the crusher. The fine material is removed via a sifter / screen, which is integrated into the crusher or downstream of it. Fig. 4, Fig. 5, and Fig. 6 show preferred variants of the method according to the invention.

[0046] Fig. 4 shows the preferred process for the use of organic binders, for example, lignin-based phenolic resins, organic single- and multi-component adhesives, preferably based on CO2-neutral or -negative raw materials. The input material is particulate solid carbon [8], which is fed to the crusher [9]. The coarse components are passed through the modified sorter

[0010] , which separates the non-crushed particles and returns them to the input material. The output of the sorter is the coarse fraction

[0013] for the structural material [4]. Fine components are separated by the sifter / screen

[0011] and used as the fine fraction

[0012] for the filler material [3].

[0047] The coarse fraction serves as structural material, and the fine fraction serves as filler material for the setting reaction. To initiate the setting reaction, both components and the liquid binding material

[0020] are fed into a mixer

[0022] . The output is solid carbon concrete

[0023] for the casting or printing of components and structures. The setting reaction takes place within the component or structure. The setting temperature can be controlled by heating or cooling.

[0048] Fig. 5 shows the preferred process for the use of inorganic binders such as hydraulic pozzolans, volcanic ash, fly ash, slag, hydraulic clays, or non-hydraulic limes and gypsums. In this variant, the fine fraction

[0012] is mixed with the dry binding material

[0020] , producing a mixed material consisting of filler and binding material

[0021] as output. This mixed material is provided as input material for the setting reaction. To prepare for the setting reaction, the mixed material

[0021] is fed into a mixer

[0022] together with the structural material

[0013] . The setting reaction is then initiated by adding water or a solvent / reactant

[0024] .

[0049] Fig. 6 shows a preferred process in which surface functionalization has been incorporated. The process can utilize a variety of functionalization reactions for both the fine fraction

[0012] and the coarse fraction

[0013] by introducing the surface functionalization material

[0014] into mixers or reactors for the surface functionalization of the filler material

[0015] or the surface functionalization of the structural material

[0016] . The output material is surface-functionalized filler material

[0017] and / or surface-functionalized structural material

[0018] . The functionalization reactions employed can have a hydrophobizing, hydrophilizing, or fine-structure-improving effect. Reactive chemical functionalities can also be synthesized on the surface for chemical crosslinking using a corresponding chemically reactive binder.

[0050] In all variants (Fig. 4-6), the filler material component can also be supplemented or formed by solid carbon from the plasma and melt bed process (direct, pelletized or ground).

[0051] Literature and sources:

[0052] 1. Waste hydrogenation: see PCT patent PCT-DE2019000158

[0053] 2. CarbonAir: see https: / / carbonair.de

[0054] 3. Rotor crushers and mills for sand production: see https: / / www.at- minerals.com / de / artikel / at Nach Rezept-1730410.html

[0055] 4. Roller crusher for coke: see http: / / aztech- brecher.de / produkte / walzenbrecher /

[0056] 5. Trieur: see https: / de.wikipedia.org / wiki / Trieur Figures

[0057] Legend:

[0058] 1. Solid carbon particles / spheroids as input material

[0059] 2. Debris image of the solid carbon particle [1]

[0060] 3. Filler as fine fraction of the fragmentation process

[0061] 4. Structural material as coarse fraction of the fragmentation process

[0062] 5. Binding material / Binder

[0063] 6. Mixed solid carbon concrete for the setting reaction

[0064] 7. Mixture of filling material [3] and binding material [5] to enclose the structural material [4]

[0065] 8. Input Solid Carbon as Solid Carbon Particles [1]

[0066] 9. Smasher

[0067] 10. Modified sorting machine

[0068] 11. Sifter / Sieve

[0069] 12. Output fine fraction for filling material [3]

[0070] 13. Output coarse fraction for structural material [4]

[0071] 14. Surface functionalization material / functionalization reagent

[0072] 15. Surface functionalization of the filling material

[0073] 16. Surface functionalization of the structural material

[0074] 17. Surface-functionalized filling material

[0075] 18. Surface-functionalized structural material

[0076] 19. Mixer for producing the mixture of filling material and binding material

[0021]

[0077] 20. Binding material

[0078] 21. Mixture of filling material and binding material

[0079] 22. Mixer for producing solid carbon concrete

[0080] 23. Solid Carbon Concrete for setting / crosslinking

[0081] 24. Liquid / Water

[0082] 25. Rotation axis

[0083] 26. Breaking tools

Claims

Patent claims 1. Process for producing a building material from - particulate solid carbon - a binding material - possible further usual additives characterized in that the solid carbon particles [8] - be crushed into angular fragments in a crusher [9], - which are mixed in a mixer [22] with the binding material [20] and then - be bound to a component or structure in a setting reaction.

2. Method according to claim 1, characterized in that the crusher [9] is associated with a sieve or sifter [11], which produces a fine fraction [11] which is used as filling material for the mixture [22].

3. Method according to claim 1, characterized in that the crusher is followed by a sorter [10] which separates out non-crushed solid carbon particles and produces a coarse fraction [11] which is used as structural material for the mixture [22].

4. Method according to claim 1, characterized in that the crusher [9] - a rotating axis to which crushing tools are applied, selected from - Pin washers - Plate beater - Pendulum racket - Impact discs - and a remote collecting device selected from - Coarse-hole sieve, which is installed as a round or long-hole sieve at a distance of > 2x the projection of the crushing tools with hole widths of > 0.8x the average diameter of the solid carbon particles to be treated. - Remote collecting tray with a distance of the collecting tray to the rotation axis of > 3x the projection of the crushing tools.

5. Method according to claim 1, characterized in that separately - the angular fragments of the coarse fraction from the crusher or the downstream sorter are provided as structural material [13] for the subsequent mixing process - the fine material from the sieve or sifter [11] is provided as filling material [12] for the subsequent mixing process.

6. Method according to claim 1, characterized in that the structural material [13] and the filling material [12] are mixed in a mixer with an organic binder selected from phenolic resins based on lignin or other organic raw materials organic one-component adhesive one component of an organic multi-component adhesive 7. A method according to claim 1, characterized in that the filling material [12] is mixed in a mixer with an inorganic Binder is mixed, selected from - hydraulic pozzolans - volcanic ash - fly ash - slag - hydraulic clays or - non-hydraulic limes and gypsums, where the mixture [21] is mixed in another mixer [22] with the structural material [13] and water or a solvent [24].

8. The method according to claim 1, characterized in that the fine material [12] and / or the structural material [13] reacts with a functionalization reagent [14] in mixing reactors to form functionalized fine material [17] and / or functionalized structural material [18] and is further processed in this form.

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