WO2026027667A1

WO2026027667A1 - Process for the deposition of pyrolytic carbon material having a d/g ratio below 0.9

Info

Publication number: WO2026027667A1
Application number: PCT/EP2025/072049
Authority: WO
Inventors: Johannes BODE; Dieter Flick; Grigorios Kolios; Jonas MARTIN; Lukas Mayr; Alexander Panchenko; Laila Raquel PASIN E MATOS; Jan Henning Felix POTTBACKER; Michael Reitz; David SCHLERETH; Bernd HINRICHSEN; Thomas Wild; Philipp Mueller; Rene Backes; Joern Alexander JUDITH
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2024-08-02
Filing date: 2025-07-31
Publication date: 2026-02-05
Anticipated expiration: 2027-02-02

Abstract

The present invention comprises a process for the deposition of pyrolytic carbon material having a D/G ratio below 0.9 onto a substrate, wherein a graphitic carbonaceous material having a median pore diameter of 0.005 pm to (1) µm, an original D/G ratio of 0.1 to 0.9 and a Lc value of the crystallite sizes of 5 to 100 nm, is used as said substrate and is fed into a reactor chamber and used as bed material in the form of a fixed, fluidized or moving bed having a particle size of 0.1 mm to 10 mm, wherein hydrocarbon are also fed into said reaction chamber and pyrolyzed at a pressure of 1 to 30 bar and a temperature of 800 to 1500°C to give a hydrogen-containing product stream and solid pyrolytic carbon depositing on the bed material and wherein the carbon deposition rate of the pyrolytic carbon is kept in a range of 0.1 to 15 wt.-% by diluting the hydrocarbon feed with hydrogen to a volume ratio of H2/C1 + of 0.5 to 25, wherein 01 + stands for all hydrocarbons having one or more C-atoms in the molecule.

Description

Process for the deposition of pyrolytic carbon material having a D/G ratio below 0.9 Description

The present invention comprises a process for the deposition of pyrolytic carbon material having a D/G ratio below 0.9 onto a substrate, wherein a graphitic carbonaceous material having a median pore diameter (volume) of 0.005 pm to 1 pm, an original D/G ratio of 0.1 to 0.9 and a Lc value of the crystallite sizes of 5 to 100 nm, is used as said substrate and is fed into a reactor chamber and used as bed material in the form of a fixed, fluidized or moving bed having a particle size of 0.1 mm to 10 mm, wherein hydrocarbon are also fed into said reaction chamber and pyrolyzed at a pressure of 1 to 30 bar and a temperature of 800 to 1500°C to give a hydrogen-containing product stream and solid pyrolytic carbon depositing on the bed material and wherein the carbon deposition rate of the pyrolytic carbon is kept in a range of 0.1 to 15 wt.-% by diluting the hydrocarbon feed with hydrogen to a volume ratio of H2/C1 + of 0.5 to 25, wherein 01 + stands for all hydrocarbons having one or more C-atoms in the molecule.

State of the art

Needle coke is a high-quality petroleum coke used in the production of graphite electrodes, which are essential in electric arc furnaces for e.g. steel production. Needle coke is also used in the manufacturing of anode graphite material for lithium-ion batteries, which are widely used in portable electronic devices and electric vehicles.

In addition, graphite finds applications as lubricants and filler material due to its unique properties. Its low coefficient of friction and excellent thermal conductivity make it suitable for lubrication. Additionally, needle coke's high carbon content and fine particle size make it an effective filler material in various industries, including rubber, plastics, and adhesives, enhancing the mechanical properties and performance of these materials.

For most of these applications, needle coke is needed in a graphite structure. The process of graphitizing needle coke involves subjecting it to high temperatures, typically above 2,500°C. This process transforms the amorphous carbon structure of the coke into a highly ordered graphite structure. It involves heating the needle coke to remove impurities and align the carbon atoms, resulting in improved electrical conductivity and thermal stability. The graphitization process is critical in enhancing the quality and performance of needle coke for its various applications, such as electrodes and lithium-ion batteries.

With the rise in both battery and steel consumption worldwide, the demand for needle coke has been steadily increasing. However, the quality of needle coke has been declining due to various factors, such as the depletion of high-quality petroleum feedstock and environmental regulations as well as trade restrictions. This has led to challenges in maintaining the desired performance, resulting in efforts to develop alternative materials.

The pyrolysis of methane yields a solid carbonaceous product that can be used as carbonaceous alternative in various applications. Depending on the application, different carbonaceous products comprising either amorphous, tur- bostratic or graphitic carbon are required. “Amorphous carbon” is carbon lacking a crystalline structure. Amorphous carbon is free and usually reactive. “Turbostratic carbon” is a class of carbon materials having structure between amorphous carbon and crystalline graphite.

Raman spectroscopy is used to characterize graphene-structure (e.g. R. Escribano et al., “Raman spectroscopy of carbon-containing particles”, Vibrational Spectroscopy 26 (2001) 179-186), as the material is composed almost entirely of symmetric sp2 bonded carbon, which is represented in great detail in the Raman spectrum. The two main bands in the graphite spectrum are known as the G-band at -1582 cm-1 and the 2D-band at -2685 cm-1 . The G- band is the primary mode in graphene and graphite. It represents the planar configuration sp2 bonded carbon that constitutes graphene. The D-band is known as the disorder band or the defect band. It represents a ring breathing mode from sp2 carbon rings, although the ring must be adjacent to a graphene edge or a defect to be active. The parameter of D/G ratio, analyzed by Raman spectroscopy, is commonly used to describe the degree of graphitic structure of a carbonaceous material.

The generic term methane pyrolysis covers a wide range of different process technologies. The best known and most advanced of these are: plasma pyrolysis, pyrolysis in a metal melting & metal salt melting reactor, moving bed & fluidized bed and fixed bed processes, catalytic and non-catalytic and pyrolysis via partial combustion. They differ in the form of the energy used (thermal, electrical, etc.), the process conditions (temperature, pressure, etc.), the catalysts and/or auxiliary materials used, the process flow and the technical readiness level (TRL).

The pyrolysis of methane is known to yield primarily amorphous or turbostratic carbon as solid carbonaceous product. For some applications like batteries, steel, lubricants and filler material however, carbonaceous material comprising graphitic carbon is required.

Moving and fluidized bed reactors are disclosed for example in US 2,982,622, US 2022/0152568, US 2021/033 1918, WO 2023/57242. Many different solids (also called support, substrate or carrier) are disclosed as moving or fluidized bed material, for example inert coke or coal particle, particularly petroleum coke, acetylene coke, and ceramic carrier particles on which the pyrolytic carbon can deposit. Such petroleum coke typically has a median pore diameter of 5 pm to 20 pm, D/G ratio of 0.8 to 1.2 and a Lc value of the crystallite sizes of 1 to 5 nm.

WO 2023/57242 discloses the need of highly pure carbonaceous material as support material with a carbon content of 99 to 100 wt.-%. In addition, said support material shall have a macro-structure and a high porosity of 30 to 70 vol.-%. If the amount of inorganic is too high, unwanted reactions or fouling might block the reactor by formation of soot or catalytic side reactions. In addition, the rate of agglomeration and thus the risk of blocking the bed reactor was rated as markedly in case of the less porous material.

JP 2000 106182 discloses a process for producing an anode material for lithium batteries, comprising graphite particles and a crystalline carbon layer covering the surfaces of said graphite particles by subjecting graphite particles to a treatment for chemical vapor deposition in a fluidized bed type reactor at 900 to 1 .200° C using a mixed gas consisting of an organic substance gas and an inert gas.

Ma et al ("Threshold size for cyclic fatigue crack propagation in a pyrolytic carbon", MATERIALS LETTERS, ELSEVIER, AMSTERDAM, NL, vol. 17, no. 1-2, 1 July 1993 (1993-07-01), pages 49-53) describes pyrolytic carbon-coated graphite obtained by chemical vapor deposition of carbon in a fluidized bed on graphite as favored material for mechanical heart valve components.

WO 2024/022909 discloses the use of pyrolytic carbon obtained by deposition of pyrolytic carbon on a petroleum coke carrier material in a fixed, moving or fluidized bed at temperatures > 1000°C for controlling soil-borne plant pathogenic fungi.

Liu et al ("Improving the electrochemical properties of natural graphite spheres by coating with a pyrolytic carbon shell", NEW CARBON MATERIALS, ELSEVIER, AMSTERDAM, NL, vol. 23, no. 1 , 1 March 2008 (2008-03-01), pages 30-36) describes the modification of natural graphite speres with a pyrolytic carbon shell obtained using fluidized bed chemical vapor deposition of acetylene.

Zang et al ("Electrochemical performance of pyrolytic carbon-coated natural graphite spheres", CARBON, ELSEVIER OXFORD, GB, vol. 44, no. 11, 1 September 2006 (2006-09-01), pages 2212-2218) describes the coating of natural graphite spheres by pyrolytic carbon from the thermal decomposition of C2H2/Ar at 950°C in a fluidized bed reactor.

Therefore, carbonaceous material with a low porosity, especially low median pore diameter and thus a nano- or micro-structure, could not yet be used as support material under standard process conditions of the methane pyrolysis.

Task

It is an object of the present invention to find an alternative carbonaceous material for needle coke, which could be graphitized. Another object of the present invention is to find a process of producing pyrolytic carbon with a low D/G ratio. Another objective of the invention is to utilize pyrolytic carbon for the use in steel and silicon electrodes, batteries, as lubricants, conductive additives, performance additives in polymers and filler material.

Invention

Said carbon deposition rate can be defined by reference time unit (see equation 7) or by weight-% (see equation 8), for the features in the claim, the definition by weight-% is taken so that said carbon deposition rate is defined by: -^mC,ref . _{n n} ™-C, deposition ' ^Tref

CU_{re f} = 100 • - = 100 100 - mo The reactor specific reference residence time is defined as fol lows:

• Batch / Fixed bed: T_ref = total pyrolysis time

• Moving bed: ^Tref ⁼ mean residence time of carrier particles in the pyrolysis zone

• Fluidized bed: ^Tref ⁼ mean residence time of carrier particles in the pyrolysis zone

Reference mass in [g]:

• Batch / Fixed bed: m₀ = initial carrier mass in the reactor

• Moving bed: m₀ = merrier ' T_ref with the reactor inlet mass flow rn^_rrier in [g/s]

• Fluidized bed: m₀ = m^L^_rr,_er ■ T_ref with the reactor inlet mass flow m _arrier in [g/s] wherein

^■C, deposition is the carbon deposition rate [g/s] m_c is the carbon mass increase [g]

T_ref is the reactor specific reference residence time [s]

CD_ref is the carbon deposition rate (per reference time unit) in [wt.%].

Surprisingly, it was found that the D/G ratio and thus the degree of graphitization of the pyrolytic carbon can be modified by using said carbonaceous material as bed material in the form of a fixed, fluidized or moving bed in a hydrocarbon pyrolysis. It was found that the deposition rate is a critical factor for using such material as bed material for producing pyrolytic carbon.

Preferably, the produced pyrolytic carbon material has a D/G ratio below 0.8, more preferably below 0.7. The D/G ratio of said produced pyrolytic carbon material is preferably in the range of 0.1 to 0.8, more preferably 0.1 to 0.7, particularly in the range of 0.1 to 0.65.

Definition

01 stands for methane.

01 + stands for all hydrocarbons having one or more C-atoms in the molecule.

02+ stands for all hydrocarbon having two or more C-atoms in the molecule.

The (total) reactor feed stream includes both the external feed stream and the internally recycled hydrogen-contain- ing product stream.

Methods for determining the parameters

D/G ratio oder (ID/IG) ratio

Definition: The ratio of the intensities of the D-band (1350 cm ¹) and the G-band (1580 erm¹) in the Raman spectrum Reference: ASTM E 3220:2025: Standard Guide for Characterization of Graphene Flakes, 2025 URL: E3220 Standard Guide for Characterization of Graphene Flakes

Median pore diameter (volume)

Definition: The median of the pore size distribution is the pore diameter at which 50% of the total cumulative pore volume is smaller and 50% is larger.

Reference: ISO 15901-1 :2016. Pore size distribution and porosity of solid materials by mercury porosimetry and gas adsorption - Part 1 : Mercury porosimetry

URL: ISO 15901-1 :2016(en), Evaluation of pore size distribution and porosity of solid materials by mercury porosimetry and gas adsorption — Part 1 : Mercury porosimetry

Lc value

Definition: The Lc value is the average stack height - i.e. the average extension of a crystalline region perpendicular to the graphene plane (c-axis of the graphite structure). Lc is the length perpendicular to the reflecting planes in XRD patterns.

Reference: ASTM D5187-21. Standard Test Method for Determination of Crystallite Size (Lc) of Calcined Petroleum Coke by X-Ray Diffraction, 2021 URL: D5187 Standard Test Method for Determination of Crystallite Size (Lc) of Calcined Petroleum Coke by X-Ray Diffraction

Crystallite size (La)

Definition: La denotes the lateral extension of individual, coherently scattering domains in the plane of the graphene layers.

Fur die Bestimmung des La-Wertes in kohlenstoffbasierten Materialien gibt es keine aquivalente Norm zur Norm ASTM D5187 fur die Bestimmung des LC-Wertes.

Die Methode zur Ermittlung von La orientiert sich an der Methode, die in Biscoe & Warren beschrieben wird. Reference: Biscoe, J., & Warren, B. E. (1942). An X-ray study of carbon black. Journal of Applied Physics, 13(6), 364-371.

Particle size

Definition: The particle size is the diameter of an idealized sphere that corresponds to the real, irregularly shaped one. It corresponds to the smallest sieve perforation diameter through which the particle fits through.

Reference:

1] DIN 66165-1 :2022-06. Partikelgrblienanalyse - Siebanalyse - Teil 1 : Grundlagen, 2022 ] DIN 66165-2:2016-08. Partikelgrblienanalyse - Siebanalyse - Teil 2: Durchfuhrung, 2016 URL: Siebanalyse Unterschiedliche Siebmethoden fur vielfaltige Anwendungen

Thickness of shell

Definition: The shell thickness is the thickness of the layer of pyrolysis carbon that is deposited on a carrier particle and completely or partially covers the carrier particle.

The method for determining the layer thickness is based on the ASTM B487 standard.

Reference: ASTM B487. Standard Test Method for Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of Cross Section, 2013 URL: ASTM-B-487-yr-87-R-13.pdf

H2/C1+ ratio

Definition: H2/C1 + ratio is the ratio of the mole fraction of dilution hydrogen to the mole fraction of hydrocarbons in the gaseous feed stream of the reactor. For ideal gases, the mole fractions of the mixture components are identical to the volume fractions. These parameters were measured with a micro GC, Agilent Technologies, type 490 Micro GC.

Carbon content

Definition: The carbon content of a carbonaceous material is the ratio of the mass of carbon contained in relation to the total mass of the sample.

Determination method: CHNS method

Reference: Hendrik Wetzel. CHNS-ANALYSE / O-ANALYSE, 2025

URL: CHNS-O-Analyse - Fraunhofer IAP

Ash content

Definition: The ash content is the mass fraction of the non-combustible residues after combustion of the sample under precisely defined conditions (temperature, air supply, duration).

Reference: ISO 1172. Kohle und Asche - Asche

URL: ISO-1171-2010.pdf

Surface concentration of metallic elements

Definition: The elemental composition of the sample surface, expressed in weight-% relative to the total mass of the analyzed sample.

Determination method: Energy dispersive X-ray spectroscopy (EDX) in combination with scanning electron microscopy (SEM). The raw signal of EDX is the count rate per peak. The evaluation software translates this to the surface concentration in % by weight.

Reference: ASTM F1375-92(2020). Standard Test Method for Energy Dispersive X-Ray Spectrometer (EDX) Analysis of Metallic Surface Condition for Gas Distribution System Components, 2020.

URL: F 1375 - 92 (2020J.pdf

Trace component concentration in the gas phase

Definition: Components that occur in a carrier gas mixture in very low concentrations.

Determination method: In the FTIR technique, a Michelson interferometer records an interferogram of the intensity of broadband infrared (IR) radiation. By applying a Fourier transform to this interferogram across a wide range of wavelengths, a spectrum is generated that comprises the spectral signatures of the gaseous components present in the measurement path. Analyzing these spectral signatures allows for to determine the concentrations of many different components simultaneously using the FTIR system. Reference: DIN EN 15483:2009-02. Luftqualitat Messungen in der bodennahen Atmosphare mit FTIR-Spektroskopie, 2008.

URL: ISO-14577-1-2015.pdf

L value

Definition: The L value (luminance) is a measure of the brightness of a surface in the CIELAB color space. Determination method: The reflectivity (luminance) is determined using luminance meters.

Reference: ISO/CIE 19476:2014(en). Characterization of the performance of illuminance meters and luminance meters, 2014

URL: ISO/CIE 19476:2014(en), Characterization of the performance of illuminance meters and luminance meters e-module (Young modulus) & hardness

Definition: The modulus of elasticity is a material-physical parameter that indicates the linear relationship between stress and deformation in the elastic (reversible) deformation range.

Determination method: The hardness and modulus of elasticity of thin layers of pyrolysis carbon are measured using nanoindentation.

Reference: DIN EN ISO 14577-1. Metallische Werkstoffe- Instrumentierte Eindringprufung zur Bestimmung der Harte und anderer Werkstoffparameter- TeiH : Prufverfahren, 2024 URL: ISO-14577-1-2015.pdf

Bed Material

The graphitic carbonaceous material used as bed material in the form of a fixed, fluidized or moving bed has preferably the following properties:

The D/G ratio of said graphitic carbonaceous material is preferably below 0.8, more preferably below 0.7, even more preferably below 0.6, even more preferably below 0.5, even more preferably below 0.4. The D/G ratio of said graphitic carbonaceous material is preferably in the range of 0.1 to 0.8, more preferably 0.1 to 0.3, particularly in the range of 0.1 to 0.2.

The Lc value of the crystallite sizes of said graphitic carbonaceous material is preferably 10 to 70 nm, even more preferably 12 to 40 nm (measured by XRD).

The chemical composition of said graphitic carbonaceous material is preferably: The carbon content is preferably in the range of 98 to 99.9 wt.%, more preferably 99 wt.% to 99.95 wt.%, even more preferably 99 to 99.99 wt.%. The oxygen content is preferably in the range of 0 to 0.5 wt.%, more preferably 0 to 0.1 wt.%. The ash content, in particular Fe, Ni, Ca, Si, Al, Or, K, Mg, Mn, Pb, V and Zn, is preferably in the range 0 to 1 wt.%, more preferably 0 wt.% to 0.5 wt.%, even more preferably 0 wt.% to 0.011 wt.%. The Sulphur content is preferably in the range 0 to 500 ppm, more preferably 0 to 250 ppm, even more preferably 0 to 100 ppm. The chlorine content is preferably in the range 0 to 10 ppm more preferably 0 to 5 ppm, even more preferably 0 to 2 ppm.

Preferably, the metal-content on the outer surface (defined by the outer shell of 5 pm thickness), is preferably in the range 0 to 1 wt.%, more preferably 0 wt.% to 0.5 wt.%, more preferably 0 wt % to 0.1 wt%, even more preferably 0 wt.% to 0.01 wt.%.

The median pore diameter of said graphitic carbonaceous material is preferably in the range of 0.005 pm to 1 pm, more preferably 0.01 pm to 0.5 pm, even more particularly in the range of 0.05 pm to 0.2 pm.

Preferably, synthetic graphitic carbon, typically based on needle coke, and synthetic and natural graphites and precursors thereof can be used as bed material, said material is named “graphitic carbonaceous material” in the present invention.

Preferably, the bed material of the fixed, fluidized or moving bed consists of 90 to 100 wt.-% of said graphitic carbonaceous material and pyrolytic carbon deposited on said graphitic carbonaceous material, more preferably 95 to 100 wt.-%, even more preferably 98 to 100 wt.-%. Preferably no metal-containing catalyst is used as bed material.

Pretreatment of the carbonaceous material before feeding into the reaction chamber

The particle size of a bed material in the form of a fixed, fluidized or moving bed is typically 1 to 10 mm for a fixed bed material, 0.1 to 1 mm for a fluidized bed material and 1 to 10 mm for a moving bed material. The carbonaceous material to be upcycled is preferably sieved, grinded/milled and/or pelletized to said particle sizes.

Pyrolysis process of hydrocarbons

The process of pyrolyzing hydrocarbons to produce hydrogen and solid carbon is well described in the state of the art. Typically the pyrolysis operates at 500 to 2000°C in a pressure range from atmospheric pressure to 30 bar. Typical hydrocarbon feedstocks for pyrolysis processes are gaseous hydrocarbons, like natural gas, methane, ethane, biogas, like biomethane. Typically, natural gas contains hydrocarbons with a ratio of C1/C2+ of 3 to 100, more preferably 3 to 50, even more preferably 3 to 25, even more preferably 4 to 20, even more preferably 5 to 15.

Preferably, the said hydrocarbon pyrolysis, also called methane pyrolysis, is conducted in a moving, fluidized or fixed bed reactor, preferably at temperatures ranging from 800 to 1500°C, preferably ranging from 900 to 1400°C preferably ranging from 1000 to 1300°C, even more preferably ranging from 1100 to 1250°C, and at pressures ranging from 1 to 30 bar, preferably from 2 to 25 bar, even more preferably 3 to 20 bar, particularly 5 to 15 bar.

The conversion rate is preferably 25 to 85 %, more preferably 30 to 80 %, even more preferably 50 to 80 % (based on the hydrocarbons in the feed stream, see equation 3).

The deposition rate is a critical parameter for using graphitic carbonaceous material with low porosity. The deposition rate is preferably 0.1 to 15 wt.-%, more preferably 2 to 10 wt.-%, even more preferably 4 to 9 wt.-%, even more preferably 4 to 8 wt.-%.

The definition of the carbon deposition rate, sometimes also referred to as carbon growth rate, depends on the reactor type and is defined in the following:

The symbols and indices used are shown in Table 1.

Table 1. Symbols and indices used for describing carbon deposition and growth rates.

The carbon deposition rate in [mol,C/s] results from the molar flow of CH4 in the feed gas and the conversion rate:

Considering the molar mass of atomic carbon leads to the carbon deposition rate in [g,C/s]:

The CH4 conversion rate is calculated using the molar flow of CH4 in the feed and in the pyrolysis gas:

The carbon deposition in [g/g] is defined as:

Am_r

CD = - - m₀

The carbon deposition rate in [g/(g*s)] follows from the initial mass and the carbon deposi- tion rate in [mol,C/s]:

The total increase in carbon mass depends on the residence time of the carrier within the pyrolysis zone:

AjTlj; ^-C, deposition ’ 6

Considering the reactor volume V and the reactor type specific reference residence time leads to the carbon deposition rate per reference time unit in [-]:

The carbon deposition rate per reference time unit can also be expressed in [wt.%] as follows:

_CDref = 100 100

^J

The reactor specific reference residence time is defined as follows:

• Batch / Fixed bed: T_re? = total pyrolysis time

Reference mass in [g]:

• Batch / Fixed bed: m₀ = initial carrier mass in the reactor

• Moving bed: m₀ = m£^l i_rrier ’ T_ref with the reactor inlet mass flow rn^_rrier in [g/s]

• Fluidized bed: m₀ = in£^l i_rrier ’ T_ref with the reactor inlet mass flow rn^_rrier in [g/s] Depending on the available instrumentation and analysis methods, different ways for the practical application of the described theoretical framework for the calculation of CD_ref exist. It is important to note that the specific material property must be measured before the pyrolysis (index “0”) and after a pyrolysis time of T_ref (index “1”).

Exemplary ways of application:

• Using the Sauter mean diameter of the particle size distribution and the measured real density from helium or xylene pycnometer:

• Using a reference volume V_ref which contains the particle mass m_{buik 0 r} to determine the bulk density: c_iref ref . u ,! u ,o

• Using the measured or calculated initial carrier weight m₀ , using gas analytics for the calculation of conversion rate, using the measured of calculated molar flow rates and applying the detailed formulas given above.

Moving bed: The solid carbon mass from hydrocarbon pyrolysis deposited on one solid granule in one pass through the reactor divided by the mass of the said one solid granule before entering the reactor. The mass of the said solid particle before and after the pyrolysis is calculated by the Sauter mean diameter of the particle size distribution of the used granule. The reference residence time according to equations 7-8 is preferably between 0.1 and 15 h, preferably between 1 and 10 h and more preferably between 2 and 8 h.

Fixed bed: The solid carbon mass from hydrocarbon pyrolysis deposited on one solid granule during its residence time in the reactor divided by the mass of the said one solid granule before entering the reactor. The mass of the said solid particle before and after the pyrolysis is calculated by the Sauter mean diameter of the particle size distribution of the used granule. The reference residence time according to equations 7-8 is preferably 0.1 to 90 h, more preferably 0.25 to 50 h, more preferably 0.5 to 25 h and even more preferably 1.0 to 10 h.

Fluidized bed: The solid carbon mass from hydrocarbon pyrolysis deposited on one solid granule during one circulation through the reactor divided by the mass of the said one solid granule before entering the reactor. The mass of the said solid particle before and after the pyrolysis is calculated by the Sauter mean diameter of the particle size distribution and the real density of the used granule. In a fluidized bed, one particle can circulate multiple times through the reactor during its residence time inside the reactor. The reference residence time according to equations 7-8 is preferably 0.1 to 90 h, more preferably 0.25 to 50 h, more preferably 0.5 to 25 h and even more preferably 1 .0 to 10 h.

The deposition rate is preferably adjusted by diluting the hydrocarbon feed with hydrogen to a volume ratio of preferably H2/C1 + from 0.5 to 25, more preferably from 0.75 to 10, even more preferably from 1 to 8, even more preferably 2 to 6.

Typically, the total reactor feed stream contains preferred 50 to 95 Vol.-% hydrogen, more preferred 65 to 85 Vol% hydrogen, 5 to 50 Vol.-% hydrocarbons, more preferred 35 to 15 vol% hydrocarbons, and 0 to 3 Vol.-% inert gases, particularly nitrogen and argon.

There are several process layouts how to realize said H2/C1+, particularly H2/CH4 feed volume ratio. Without excluding further options, preferred layouts are:

Direct gas recycle: a portion of the reactor effluent gas stream is recycled without any purification steps.

Gas streams may or may not be cooled or heated.

Recycle after purification unit: The hydrogen depleted gas stream after any purification or gas separation unit is recycled to the reactor, while a fraction is purged.

Gas streams employed for pneumatic transport of solids are recycled to the reactor.

Hydrogen containing gas streams from different processes or other sources are mixed to the hydrogen feed stream.

Preferably, an internal recycle of the hydrogen-containing product stream is used to control the H2/C1 + volume ratio, that means, a portion of the raw hydrogen-containing product stream is recycled without any purification steps. Said recycled hydrogen-containing product stream may or may not be cooled, heated and/or compressed.

The hydrogen-containing product stream leaving the reaction chamber preferably enters a separation unit. This separation unit typically includes a valve, a flow meter, and a meter to determine the H2 concentration.

Preferably, 20 vol% to 90 vol% of the hydrogen-containing product stream is separated and recycled to the reaction chamber, more preferably 30 vol % to 85 vol %, more preferably 40 vol % to 85 vol %, even more preferably 50 vol % to 80 vol %. The vol% of the hydrogen-containing product stream taken for the internal direct recycle is preferably adjusted to a volume ratio H2/C1 + of the total reactor feed stream ranging from 0.1 to 25, more preferably from 0.5 to 10, even more preferably from 1 to 8.

The recycled hydrogen-containing product stream is mixed with the external feed stream, e.g. natural gas, inside or outside the reaction chamber. Before mixing, the temperature of the internally recycled hydrogen-containing product stream is preferably between 10°C 200°C, even more preferably between 15 and 150°C and in particular between 20 and 100°C. Preferably, the external feed stream and the recycled hydrogen-containing product stream are mixed before entering the rection chamber, outside of the reactor. Alternatively, the streams are separately introduced into the reaction chamber.

Ratio of internally recycled hydroqen-containinq product stream and external hydrocarbon stream (Fig. 1)

Preferably the ratio of the volume of the internally recycled hydrogen-containing product stream to the volume of the external feed stream is between 0.1 to 20, more preferably between 0.3 and 8, even more preferably between 0.8 and 6.

The total reactor feed stream preferably contains hydrocarbons with a ratio of 01/02+ of 15 to 500, more preferably 17 to 100, even more preferably 20 to 50.

Preferably, said volume ratio of the total reactor feed stream is at least increased by a factor of 1.1 to 2.5, more preferably 1 .25 to 2, compared to said volume ratio of 01/02+ of the external feed. Therefore, the feed of the pyrolysis process contains at least two feed streams: (i) external feed stream containing hydrocarbons, preferably gaseous and liquid hydrocarbons, more preferably gaseous hydrocarbons, even more preferably methane and/or other light hydrocarbons feed stream, preferably natural gas and (ii) an internally recycled hy- drogen-containing product stream.

Hydroqen-containinq feed stream

The methane pyrolysis results in a hydrogen-containing product stream and solid carbon.

Depending on the reaction conditions, the content of the hydrogen-containing product stream - related to the total volume of the hydrogen-containing product stream - is preferably:

(i) hydrogen preferably between 30 vol% and 99 vol%, more preferably between 50 vol% and 98 vol%, and in particular between 60 vol% and 98 vol%,

(ii) methane preferably between 1 and 60 vol%, more preferably between 2 and 40 vol% and in particular between 2 and 30 vol%,

(iii) the sum of the contents of all C2+ hydrocarbon components comprising e.g. C2H6, C2H4, C2H2, C3H8, C3H6, C3H4, C4H8, C4H6, C6H6, C7H8, C8H10 preferably between 0 and 1 mol%, more preferably between 0 and 0.5 mol% and in particular between 0 and 0.1mol%,

(iv) nitrogen preferably between 0 and 20 vol%, more preferably between 0 and 10 vol% and in particular between 0 and 5 vol%, carbon monoxide preferably between 0 and 2vol%, more preferably between 0 and 1 vol% and in particular between 0 and 0.5 vol%, carbon dioxide preferably between 0 and 2vol%, more preferably between 0 and

1 vol% and in particular between 0 and 0.5 vol% and the water preferably between 0 and 2vol%, more preferably between 0 and 1 vol% and in particular between 0 and 0.5 vol%.

The hydrogen-containing stream preferably contains hydrocarbons with a ratio of C1/C2+ of 4 to 10000, more preferably 15 to 1000, even more preferably 20 to 500, even more preferably 30 to 250, even more preferably 50 to 200.

The methane pyrolysis process can be heated in different ways known to the persons skilled in the art: heated carrier gas, resistance heating, induction or autothermal, (partial) combustion. Preferably the methane pyrolysis process is heated electrically, even more preferably by resistive heating (Joule heating) of the solid material as described for example in US 2982622, WO 2019/145279 and WO 2020/200522.

Pretreatment or temporarily treatment

Preferably, before the process step of pyrolyzing of hydrocarbons the bed material is pretreated, even more preferably if the oxygen and ash content higher than 1 wt.-%.

For this pre- or temporarily treatment preferably an atmosphere of hydrogen and/or inert gases is used. Preferably the atmosphere contains 70 to 100 VoL-%, related to the total atmosphere used for the treatment, of hydrogen and/or inert gases like nitrogen, argon, helium; more preferably 80 to 100 Vol.-% of hydrogen and/or inert gases, more preferably 90 to 100 VoL-%, even more preferably 95 to 100 Vol.-%. The atmosphere contains 30 to 0 Vol.-% of gaseous hydrocarbons, preferably 20 to 0 VoL-%, more preferably 10 to 0 VoL-%, more preferably 5 to 0 VoL-%, even more preferably 2 to 0 VoL-%, the methane content in said gaseous hydrocarbons is preferably 85 to 100 VoL-%, more preferably 90 to 100 VoL-%, even more preferably 95 to 100 VoL-%, in particular 99 to 100 Vol.-%.

The time and temperature of said treatment is characterized by the formula T = time (min) multiplied by temperature (°C) and the T is at least 10000 (min °C) and wherein the temperature is at least 500°C. Preferably T is at least 20000 (min °C), more preferably T is at least 50000 (min °C), even more preferably T is at least 100000 (min °C). Preferably T is in the range of 3000 to 1500000 (min °C), more preferably in the range of 10000 to 900000 (min °C) ), more preferably in the range of 50000 to 700000 (min °C), even more preferably in the range of 100000 to 300000 (min °C)

Preferably the temperature of said treatment is at least 600°C, more preferably at least 700°C, more preferably at least 800°C, more preferably at least 900°C, even more preferably at least 1000°C. Preferably the temperature of said treatment is in the range of 500°C to 2500°C, more preferably in the range of 600°C to 2000°C, more preferably in the range of 1000°C to 1500°C, even more preferably in the range of 1200°C to 1400°C.

The time of said treatment is at least 5 min, more preferably at least 30 min, more preferably at least 60 min, more preferably at least 90 min, more preferably at least 120 min, even more preferably at least 180 min.

Preferably the time/period of said treatment is in the range of 5 min to 10 days, preferably 5 min to 5 days, more preferably 5 min to 3 days, more preferably 5 min to 1 day, more preferably in the range of 10 min to 12 hours, even more preferably in the range of 30 min to 720 min. If a moving bed is using, the time/period of said treatment is preferably at least one passage of the solid material (moving bed) through the reactor (residence time), more preferably at least two passages through the reaction. Preferably one to ten passages of the moving bed through the reactor, more preferably one to five passages, even more preferably one to four passages, even more preferably two to four passages, even more preferably one to two passages. The operating time in pre-treatment mode preferably exceeds the treatment time required for a single particle. This is due to two main factors: first, a transition period is necessary to switch between production mode and pre-treatment mode, allowing for the adjustment of operating conditions and stabilization of the system to the desired target state. Second, pre-treatment is performed on a larger quantity of material to ensure sufficient supply for the intended runtime of the subsequent production cycle.

Alternatively, the pre-treatment can be controlled until the carrier material meets specific criteria. For example, the composition of the outflowing gas stream can be measured, preferably using FTIR according to DIN EN 15483:2009- 02. Key components of interest include carbon monoxide, carbon dioxide, water vapor, and hydrogen sulfide. Pretreatment continues until the concentration of these components drops below a specified threshold. The cumulative mole fraction of H2O, CO, CO2, H2S, CS2, and COS should be less than 1 vol.-%, preferably less than 0,5 vol.-%, and particularly less than 0,1 vol.-%, especially less than 0.05 vol.-%.

Additionally, the surface concentration of metallic elements on the carrier and/or the loading of the carrier with pyrolysis carbon serves as a measure of pre-treatment effectiveness. The surface concentration, defined as the mass of metal impurities relative to the outer surface of the carrier particles, should be determined semi-quantitatively by SEM/EDX according to ASTM F 1375-92(2020). The acceptable surface concentration of metallic impurities should be less than 0.1 mg/cm² to 1 mg/cm².

During said treatment, the carbon deposition rate of the pyrolysis process, if any, is preferably below 5 wt.-%, more preferably below 2 wt.-%, even more preferably below 1 wt.-%. Preferably, the deposition rate during said treatment is in the range of 0 to 5 wt.-%, more preferably 0 to 2 wt.-%, even more preferably 0 to 1 wt.-%.

During said treatment, the conversion rate of the pyrolysis process, if any, is preferably below 75 %, more preferably below 50 %, even more preferably below 30 %, even more preferably below 20 % (based on the hydrocarbons in the feed stream). Preferably, the conversion rate during said treatment is in the range of 0 to 75 %, more preferably 0 to 50 %, even more preferably 0 to 30 %, even more preferably 0 to 20 %.

During said treatment, the hydrocarbons if any contained in the treatment atmosphere have a volume ratio of C1/C2+ of 15 to 500, more preferably 17 to 100, even more preferably 20 to 50.

Adaption of the process parameters and pretreatment

The concrete preferred process conditions are depending on the bed material used. In principle, a person skilled in the art preferably adapts the process conditions of the optional pretreatment and the hydrocarbon pyrolysis as follows:

1 . Making an elemental analysis of the bed material.

2: Preferably, adjusting the pretreatment to the chemical composition: the higher the oxygen and ash content of the bed material the lower the deposition rate during the first operation time of the pretreatment. If oxygen and/or ash content is higher than 1 w.-%, pretreatment is preferred. Said pretreatment can preferably end, if an low content of oxygen containing site product, like water CO, CO2 is reached in the hydrogen containing product stream, e.g. water below 0.01 vol.-% and CO below 250 ppm, are present. After that, the pyrolysis process can preferably be started.

3. Adjusting the process conditions of the pyrolysis conditions, especially the deposition rate, preferably start with a low deposition rate like 1 wt.-% deposition and slowly increasing the deposition rate as the operation time increases, e.g. increase of 1 wt.-% in deposition rate after 10 min to 1 hour of operation time or increase of 1 wt.-% in deposition rate per passage of the bed material through a moving bed reactor.

Preferred Process Conditions: Moving Bed

Preferably the solid material (also called substrate) is guided in form of a moving bed through the reaction chamber, with methane and/or other light hydrocarbons being passed advantageously in countercurrent to the substrate.

For this purpose, the reaction chamber is preferably designed as a vertical reactor, which means that the movement of the moving bed is gravity driven. Flow through the moving bed is taking place, advantageously, homogeneously, and uniformly (see for example WO 2013/004398, WO 2019/145279 and WO 2020/200522). Methane and/or other light hydrocarbons are preferably introduced via the bottom of the reactor, preferably having a temperature of 10 to 200°C. The substrate is preferably introduced via the top of the reactor, preferably having a temperature of 10 to 200°C. The hydrogen-containing product gas is preferably taken off via the top of the reactor, preferably having a temperature of 10 to 200°C. The granular pyrolytic carbon is preferably taken off via the bottom of the reactor, preferably having a temperature of 10 to 200°C.

The discharged carbon is preferably at least partly recycled and introduced into the reactor again using it as substrate for the moving bed. As a result, a continuous process of the moving bed is achieved. The recycled carbon can optionally be mixed with fresh, initial solid material. The flow velocity of the substrate is advantageously in the range of 0.005 to 6.0 cm/s, more preferably 0.005 to 0.5 cm/s. The flow velocity of the gas flow is advantageously in the range of 0.025 to 10 m/s, more preferably 0.025 to 2 m/s. The gas residence time in the reactor is advantageously between 0.1 and 50 s, preferably between 1 and 20 s. The residence time of the substrate is preferably between 0.1 and 15 hours, preferably between 1 and 10 hours and more preferably between 2 and 8 hours.

Solid material

The solid material, also called substrate or carrier material, is preferably a granular material. The particle size of a preferred substrate is in the range of 0.1 to 10 mm, preferably 0.3 to 8 mm.

The preferred substrate is a carbon-containing substrate, for example calcined petcoke (CPC), green coke, anode butts, bio char, recycled carbon black (from polymer recycling via pyrolysis), black mass (battery recycling) or the pyrolytic carbon itself. The carbon content is preferably in the range of 70 to 99 wt.%, more preferably 90 wt.% to 99.9 wt.%, more preferably 99 to 99.95 wt.%, even more preferably 99 to 99.99 wt.%.

The oxygen content is preferably in the range of 20 to 0.001 wt.%, more preferably 5 wt.% to 0.1 wt.%, more preferably 1 wt % to 0.5 wt%.

The ash content, in particular Fe, Ni, Ca, Si, Al, Cr, K, Mg, Mn, Pb, V and Zn, is preferably in the range 20 to 0.001 wt.%, more preferably 5 wt.% to 0.1 wt.%, more preferably 1 wt % to 0.5 wt%.

The Sulphur content is preferably in the range 5 to 0.0001 wt.%, more preferably 0.5 wt.% to 0.01 wt.%, more preferably 0.1 wt % to 0.01 wt%.

The chlorine content is preferably in the range 1 to 0.00001 wt.%, more preferably 0.1 wt % to 0.001 wt%, even more preferably 0.01 wt.% to 0. 1 wt.%.

Preferably, the metal-content on the outer surface (defined by the outer shell of 5 pm thickness), is preferably in the range 20 to 0.001 wt.%, more preferably 5 wt.% to 0.001 wt.%, more preferably 1 wt % to 0.001 wt%, even more preferably 0.5 wt.% to 0.001 wt.%.

The BET surface area of the substrate is preferably between 0.001 and 100 m2/g, preferably 0.1 and 100 m2/g, more preferably 0.01 and 50 m2/g, even more preferably 0.1 and 50 m2/g, even more preferably 0.05 to 30 m2/g, in particular 0.1 to 30 m2/g. Typically, the porosity of the solid material is between 0.1 % to 90%, preferably between 1% to 80%, even more preferably 30% to 70% according to WO 2023/057242, even more preferably 30% to 60% (Hg po- rosimetry, DIN66133).

Preferably, the density of the substrate is in the range of 1.5 to 2.5 g/cc (real density in xylene, ISO 8004). Preferably, the bulk density of the substrate is in the range of 0.5 to 1 .5 g/cc.

Pyrolytic granular carbon

Typically, the density of the deposited pyrolytic carbon produced via the described methane pyrolysis process is in the range of 1.5 to 2.5 g/cc, preferably 1 .7 to 2.4 g/cc, even more preferably 2.0 to 2.3 g/cc (real density in xylene, ISO 8004). Typically, the bulk density of the pyrolytic carbon is in the range of 0.5 to 1.5 g/cc, more preferably 0.7 to 1 .3 g/cc.

Typically, the ash content of the pyrolytic carbon is in the range of 0.001 to 1 wt-%, preferably 0.01 to 0.2 wt-%. Typically, the carbon content is in the range of 98 to 100 wt-%, more preferably 99.5 to 100 wt-%, even more 99.75 to 100 wt-%, even more 99.9 to 100 wt-%.

Typically, the porosity of the granular pyrolytic carbon is between 0% to 15%, preferably 0.2% to 10%, most preferably 0.2% to 5% (Hg porosimetry, DIN66133). Typically, the specific surface area of the pyrolytic carbon measured by Brunauer-Emmett-Teller (BET) is in the range of 0.001 to 20 m2/g, preferably 0.001 to 10 m2/g, even more preferably 0.05 to 5 m2/g.

Preferred Moving Bed Method

Preferably a moving bed technology is used for the methane pyrolysis of the present invention comprising:

- a plurality of solid substrates is guided into the first heat integration zone and from there into the reaction zone,

- the solid substrates are heated in the reaction zone,

- the solid substrates are guided from the reaction zone into the second heat integration zone and are withdrawn from the second heat integration zone,

- methane is introduced into the second heat integration zone and from there into the reaction zone, wherein methane in the second heat integration zone is heated against solid substrates coming from the reaction zone, wherein the solid substrates are cooled, and wherein the methane is contacted with the heated solid substrates in the reaction zone, wherein heat from the heated solid substrates is transferred to methane in order to heat methane in the reaction zone, wherein methane is decomposed to hydrogen and granular pyrolytic carbon in the reaction zone,

- hydrogen produced is guided from the reaction zone into the first heat integration zone, wherein the solid substrates in the first heat integration zone are preheated against hydrogen coming from the reaction zone, wherein hydrogen is cooled, and wherein

- hydrogen is withdrawn from the first heat integration zone

- granular pyrolytic carbon produced is deposited on solid substrates and withdrawn with the substrates

- withdrawn substrate is preferably at least partly recycled and introduced into the reactor

- withdrawn hydrogen is preferably at least partly recycled and introduced into the reactor.

Preferred Reactor

Preferably, the reactor for carrying out the methane pyrolysis, in which hydrogen and pyrolytic carbon are produced from hydrocarbons, preferably methane, comprises: a reactor surrounding a reactor interior the reactor is configured to provide a gravity-driven moving bed in a reaction zone of the reactor interior, which gravity-driven moving bed comprises a large number plurality of solid substrates, wherein the reactor is also configured to guide methane into the reaction zone, wherein, in order to heat methane, the reactor is configured to heat the solid substrates in the reaction zone by generating an electric current in the solid substrates between a pair of first and second electrodes such that, by transferring heat from the solid substrates to methane, methane in the reaction zone can be heated to a reaction temperature to produce hydrogen and granular pyrolytic carbon, and wherein the reactor interior also comprises a first heat integration zone in which heat from hydrogen produced in the reaction zone can be transferred to solid substrates of the reactor gravity driven moving bed which are to be guided into the reaction zone, and wherein the reactor interior also comprises a second heat integration zone in which heat from solid substrates of the reactor gravity driven moving bed coming from the reaction zone can be transferred to methane in order to preheat methane, wherein said reaction zone is arranged between said pair of first and second electrodes and said first heat integration zone is arranged above said first electrode and said second heat integration zone is arranged below said second electrode.

The volume of the reaction section is preferably 1 m3 to 1000 m3, preferably 5 m3 to 750 m3, more preferably 0.5 m3 to 500 m3. The height of the reaction section is preferably 0.1 m to 50 m, preferably 0.5 to 20 m, more preferably 1 m to 10 m.

The said moving bed reactor has several advantageous compared to other reactor types.

Heat integration enables a high efficiency since gas and solid are leaving the reactor at temperatures between 10 °C - 200 °C

No additional equipment for heat recovery or special equipment for handling of gas solids with temperatures above 200 °C required.

Reproduceable carbon quality: Each particle is treated under the same conditions in the moving bed. Same residence time for each solid particle in the reaction zone.

Preferred Fixed Bed Method

Preferably a fixed bed technology is used for the methane pyrolysis of the present invention comprising:

- a plurality of solid substrates having a particle size of 0.5 to 10 mm is introduced into the reactor and fixed in the reaction zone, preferably the substrates are introduced via the top of the reactor,

- the solid substrates are heated in the reaction zone, preferably the solids are electrically heated, more preferably the solids are heated via a direct electric Joule heating,

- methane is introduced into the reaction zone, wherein the methane is contacted with the heated solid substrates in the reaction zone, wherein heat from the heated solid substrates is transferred to methane in order to heat methane in the reaction zone and wherein methane is decomposed to hydrogen and pyrolytic carbon that is deposited on the solid substrates in the reaction zone, preferably methane is introduced via the top of the reactor,

- hydrogen is withdrawn from the reaction zone, preferably from the bottom of the reactor

- By feeding hydrocarbon from the top into the reactor, the gas velocity is not limited by the fluidization regime of the solid particles, which allows higher space time yields compared to moving bed or fluidized bed reactors. Gas velocities in the reaction zone (calculated for an empty reactor) are 0,5 - 15 m/s and more preferred 1 - 10 m/s. In addition, the residence time of the su bstrate ca n be increased to 2 to 24 ho u rs.

- batchwise the solid substrates with pyrolytic carbon deposited on it are withdrawn from the reaction zone

- withdrawn hydrogen is preferably at least partly recycled and introduced into the reactor. Fixed bed reactors are known in the state of the art, e.g. [1] Eigenberger, Ruppel, Ullmanns’s encyclopedia of industrial chemistry Catalytic Fixed-Bed Reactors, 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Typically, several fixed bed reactors are combined in a cyclic mode operation e.g. One reactor is in production mode and carbon is deposed in the fixed bed until the maximum carbon deposition is reached. While the carbon is removed from this reactor, the next reactor starts with production and so on. With this cyclic operation mode, a continuous production is ensured.

Preferred Fluidized Bed Method

Preferably a fluidized bed technology is used for the methane pyrolysis of the present invention comprising:

- a plurality of solid substrates having a particle size of 0.1 to 10 mm is introduced in the fluidization zone, the reaction zone, and placed on a distributor o optionally the substrates are heated externally and are introduced into the reactor at a temperature of 800 °C to 1500 °C

- optionally the solid substrates are heated in the reaction zone, preferably the solids are electrically heated,

- methane is introduced into the reactor via the bottom, distributed by the distributor fluidizing the solid substrates and guided through the reaction zone wherein methane is contacted with the heated solid substrates in the reaction zone, wherein heat from the heated solid substrates is transferred to methane in order to heat methane in the reaction zone, wherein methane is decomposed to hydrogen and pyrolytic carbon that is deposited on the solid substrates in the reaction zone, o The Hydrocarbon concentration of the feed gas ranges preferably from 20 vol% - 100 vol %, more preferably form 60 vol% to 100 vol % o Due to the relative motion of the particles in a fluidized, carbon deposition rates from the pyrolyzed gas on the solid granule per pass through the reactor are preferred above 10 w% and more preferred above 20 w%. The relative deposition is related to the mean solid particle mass flux out of the reactor. o The pressure is preferably 1 to 10 bar.

- hydrogen is withdrawn from the reaction zone, preferably from the top of the reactor

- preferably continuously, the solid substrates with pyrolytic carbon deposited on it are withdrawn from the reaction zone

Fluidized bed reactors are known in the state of the art, e.g[2], Werther, Ullmanns’s encyclopedia of industrial chemistry Fluidized Bed-Reactors, 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A fluidized bed reactor may have more than one stage as described in W02022081170 and US20210331918.

H2 Purification

The part of the hydrogen-containing product stream that is not internally recycled into the reaction chamber is typically purified in a removal apparatus, e.g. using adsorption or membrane technologies.

For example, the gaseous product stream can still contain hydrogen sulfide. Hydrogen sulfide can preferably be removed from the gaseous product stream via gas scrubbing, e.g. via ZnO, CuZnO, Fe(OH)3, Zeolites, MOFs, as known in the state of the art. Typical process conditions of the gas scrubbing are 60 to 180°C and 1 to 100 bar.

For example, the gaseous product stream can still contain carbon oxide and inert gases, e.g. nitrogen. Corresponding hydrogen recovery apparatuses are common knowledge to the person skilled in the art, for example pressure swing adsorption or permeation.

Recycle of purification off-gas

Preferably, a part of the off-gas from the hydrogen recovery is additionally internally recycled to the reaction chamber, preferably 5 to 100 vol.-% of the total off-gas, more preferably 10 to 98 vol.-%, even more preferably 25 to 95 vol.-%, even more preferably 50 to 95 vol.-% even more preferably 70 to 95 vol.-% even more preferably 80 to 95 vol.-%. Preferably, the remaining part of said total off-gas from the hydrogen recovery is withdrawn. The preferred percentage of recycle and withdrawal is dependent on the amount of inert gases in the hydrogen-containing product stream, especially on the nitrogen content.

Pyrolytic carbon shell

The present invention further relates to pyrolytic carbon shell and particles having a pyrolytic carbon shell, wherein the outer surface (defined by the outer shell of 5 pm thickness) of said pyrolytic carbon shell has:

(i) D/G ratio 0.1 to 0.8, preferably 0.1 to 0.7, particularly 0.1 to 0.65

(ii) Carbon content 98 to 99.99 wt.-%, preferably 99 to 99.99 wt-%, more preferably 99.5 to 99.99 wt.-%

(iii) Thickness of the shell from 10 pm to 10 mm, preferably 100 pm to 5 mm, 200 pm to 1 mm

(iv) Preferably Particle size from 0.11 to 20 mm, more preferably 0.6 to 12 mm, preferably 0.5 to 10 mm, more preferably 1 to 8 mm (v) Ash content 0 to 2 wt-%, preferably 0 to 1 wt-%, more preferably 0 to 0.5 wt.-%

(vi) Sulfur content 0 to 0.5 wt-%, preferably 0 to 0.3 wt-%, more preferably 0 to 0.1 wt.-%

(vii) Specific surface area 5 to 25 m2/g, preferably 5 to 20 m2/g, more preferably 8 to 15 m2/g

(viii) Median pore diameter from 0.005 to 0.1 m,

(ix) e-module being in the range of 5 to 35 GPa and

(x) hardness being in the range of 0.2 to 5 GPa,

The present invention also comprises a core-shell particle comprising a core comprising graphitic carbonaceous material having a median pore diameter of 0.005 m to 1 pm, preferably 0.01 pm to 0.5 pm, more preferably 0.05 pm to 0.2 pm, an original D/G ratio of 0.1 to 0.8, preferably 0.1 to 0.3, particularly in the range of 0.1 to 0.2 a Lc value of the crystallite sizes of 5 to 100 nm, preferably 10 to 70 nm, even more preferably 12 to 40 nm and a shell of pyrolytic carbon from a hydrocarbon pyrolysis having a D/G ratio in the range of 0.1 to 0.8.

Preferably the core diameter of the core is from 0.1 mm to 10 mm, more preferably 0.5 to 8 mm. Preferably the thickness of the shell is from 10 pm to 10 mm, preferably 100 pm to 5 mm, 200 pm to 1 mm.

The core is at least partially coated by pyrolytic carbon obtained by thermal decomposition of hydrocarbons, the shell; preferably, the core is completely coated by said pyrolytic carbon resulting in a closed outer layer, the shell.

Post-Processing of the pyrolytic granular carbon

Typically, said pyrolytic carbon and/or said core-shell particle is post-processed. Typical methods of post-processing are milling, screening, sieving, coating, doping, blending and/or thermal treatment. A thermal treatment would lead to a graphitized carbon material. Such thermal treatments are known in the state of the art and typically conducted in an electric resistance/inductive oven, using a temperature of 2000 to 3000°C, at atmospheric pressure or below, in an inert atmosphere, in particular argon. The particle residence time under graphitization conditions depends on many factors like, e.g., the number of particles to be graphitized, the particle size, the technology used and the temperature level. Residence times in established processes like Acheson or Lengthwise furnaces typically range from hours to days while residence times in alternative technologies like microwave or laser processes range from seconds to minutes. In principle: the longer the residence time and the higher the temperature, the better the degree of graphitization.

Advantages for the post-processing step of graphitization:

• Said pyrolytic carbon has a higher purity, in particular lower sulfur content as state of the art material like Needle Coke and thus leads to a more effective graphitization as sulfur interferes with graphite formation

• High potential for significant CO2 reduction during the graphitization production, NeedleCoke is based on aromatic oils and is produced using the delayed coking process with subsequent calcination, said process is very energy-intensive and therefore emits a lot of CO2

General Advantages

In terms of mechanical properties, graphite exhibits higher tensile strength, Young's modulus, and hardness compared to amorphous carbon. Its layered structure allows for easy sliding of the graphene layers, resulting in good lubricating properties. These mechanical characteristics make graphite a preferred material in applications where mechanical stability and strength are required, such as in structural components, lubricants, and friction materials. The high crystallinity of carbon offers several advantages in various applications:

1. Structural strength: High crystallinity in carbon materials, provides exceptional mechanical strength. This makes them ideal for applications where high tensile strength and stiffness are required, such as aerospace components, automotive parts, and sporting equipment.

2. Electrical conductivity: Highly crystalline carbon materials exhibit excellent electrical conductivity due to the ordered arrangement of carbon atoms. This property is important in applications such as electrodes in metallurgy, electronics, batteries, fuel cells, and conductive additives where efficient electrical conduction is crucial.

3. Thermal conductivity: High crystallinity in carbon materials, such as graphite, enables efficient thermal conductivity. This makes them suitable for applications where heat dissipation is essential, including heat sinks, thermal management systems, and electronic devices.

4. Chemical stability: The high crystallinity of carbon materials enhances their chemical stability, making them resistant to degradation and corrosion. This property is valuable in applications such as chemical processing, catalyst supports, and electrodes in harsh environments.

Description of the Figures

Figure 1 presents a schematic drawing of the internal recycling of the hydrogen-containing product stream Figure 2: The diagram shows the isolines of carbon deposition (CD) depending on temperature and CH4 concentration in feed gas, where CDi < CDii < CDiii Figure 3 presents a comparison of the morphology of the initial carrier (a) and the carrier coated with pyrolysis carbon (b) before and after inventive example III.

Example

1. D/G ratios

Comparative example I:

Pyrolysis of natural gas was performed in a ohmic heated moving bed reactor. The reactor had a length of 3 m and an inner diameter of 200 mm. The reactor was initially filled with calcined petroleum coke (CPC) with a particle size distribution of 2 - 4 mm. The reactor was directly electrically heated to temperatures of 1250 °C. To compensate for heat losses, the reactor was additionally wall-heated. The reactor was continuously operated at a pressure of 2.4 bara, and the carbon granules were recycled and passed 10 times through the reactor.

Comparative example II:

Pyrolysis of methane was carried out in a fixed bed reactor. The utilized reactor was a fixed bed reactor filled over a total height of -555 mm with solid carbon granule (acetylene coke) in a ceramic tube with an inner diameter of 50 mm. A mixture of 20 vol-% methane in hydrogen was used as feed mixture. Pyrolysis was carried out for 4 h at a reactor pressure of 1 bara and a temperature of 1300 °C.

Inventive example I:

Pyrolysis of methane was carried out in a fixed bed reactor. The utilized reactor was a fixed bed reactor filled over a total height of -555 mm with granular graphite particles (Ranco 9904) in a ceramic tube with an inner diameter of 50 mm. A mixture of 20 % natural gas in hydrogen was used as feed mixture. Pyrolysis was carried out for 4 h at a reactor pressure of 1 bara and a temperature of 1300 °C.

Inventive example II:

Pyrolysis of methane was carried out in a fixed bed reactor. The utilized reactor was a fixed bed reactor filled over a total height of -555 mm with natural graphite ore in a ceramic tube with an inner diameter of 50 mm. A mixture of 20 % natural gas in hydrogen was used as feed mixture. Pyrolysis was carried out for 1 h at a reactor pressure of 1 bara and a temperature of 1300 °C.

Inventive example III:

Pyrolysis of methane was carried out in a fixed bed reactor. The utilized reactor was a fixed bed reactor filled over a total height of -555 mm with granular graphite particles (Ranco 9904)in a ceramic tube with an inner diameter of 50 mm. A mixture of 20 % natural gas in hydrogen was used as feed mixture. Pyrolysis was carried out for 2,5 h at a reactor pressure of 1 bara and a temperature of 1450 °C. The change in morphology due to pyrolysis is shown in Figure 3.

2. Proof of Concept under commercial conditions

Pyrolysis of methane was carried out in total six cycles in a fixed bed reactor. The utilized reactor was a fixed bed reactor filled over a total height of -560 mm with granular graphite particles (Ranco 9904) in a ceramic tube with an inner diameter of 40 mm. After each cycle the carbon fixed bed was removed fraction wise (7 fractions in total) from the reactor and small analysis samples were taken. The fractions of the carbon bed were then refilled in the reactor presenting the fixed bed for the next cycle. All cycles of pyrolysis were performed at the following conditions: 1450°C, 10 bara, 120 Nl/h CH4, 480 Nl/ H2. In total, a significant amount of 30 wt.% of PyroC were deposited over the 6 cycles of pyrolysis, showing that high contents of PyroC can also be synthesized on a graphite carrier. 3. Small pore versus large pores

Pyrolysis of methane was carried out in three experiments in a fixed bed reactor. The only difference between the three experiments was the used granular carbon particles that formed the fixed bed and a reduced reaction time in experiment three. Otherwise, the same reactor and operation conditions were used in both experiments. The utilized reactor was a fixed bed reactor filled over a total height of -555 mm with granular carbon particles with a particle size distribution of 3 - 8 mm in a ceramic tube with an inner diameter of 50 mm. A mixture of 20 % methane in hydrogen was used as feed mixture. Pyrolysis was carried out in experiment 1 and 2 for 4 h and for experiment 3 for 1 .5 h at a reactor pressure of 1 bara and a temperature of 1300 °C. In the first experiment a carbon carrier with large pores, characterized by a median pore diameter (volume) of 47 pm was used. The resulting carbon particles at the end of the experiment had a median pore diameter (volume) of 32 pm. The bed of the first experiment was only gently agglomerated (1 .5). In the second experiment a carrier with a significantly smaller median pore diameter (volume) of 0.11 pm was obtained at the end of the pyrolysis and the carbon bed was strongly agglomerated (4) in the second experiment with a carrier with small pores. In the third experi- ment the same carrier resulting from the second experiment was used (starting median pore diameter (volume) of 0.11 pm. Despite a significant reduction in the pyrolysis time from 4 to 1 .5 h the bed of the third experiment was again strongly agglomerated (4).

Claims

Claims:

1. A process for the deposition of pyrolytic carbon material having a D/G ratio below 0.9 onto a substrate material, wherein a graphitic carbonaceous material having a median pore diameter of 0.005 pm to 1 pm, an original D/G ratio of 0.1 to 0.9 and a Lc value of the crystallite sizes of 5 to 100 nm, is used as said substrate and is fed into a reactor chamber and used as bed material in the form of a fixed, fluidized or moving bed having a particle size of 0.1 mm to 10 mm, wherein hydrocarbon are also fed into said reaction chamber and pyrolyzed at a pressure of 1 to 30 bar and a temperature of 800 to 1500°C to give a hydrogen-containing product stream and solid pyrolytic carbon depositing on the bed material and wherein the carbon deposition rate of the pyrolytic carbon is kept in a range of 0.1 to 15 wt.-% by diluting the hydrocarbon feed with hydrogen to a volume ratio of H2/C1 + of 0.5 to 25, wherein C1 + stands for all hydrocarbons having one or more C-atoms in the molecule

2. Process according to claim 1, wherein the deposition rate is kept in a range of 2 to 10 wt.-%, wherein said carbon deposition rate is defined by:

^Tref . _v km'C_iref . _{n r}, ff ™C, deposition ... , . - - ^-C, deposition ’ tref

CD_ref — 100 • - = 100 • I I - av at = 100 - m₀ JJ m₀ m₀ t=o wherein the reactor specific reference residence time is defined as follows:

• Batch / Fixed bed: x_ref = total pyrolysis time

• Fluidized bed: ^Tref ⁼ mean residence time of carrier particles in the pyrolysis zone reference mass in [g] :

• Batch / Fixed bed: m₀ = initial carrier mass in the reactor

• Moving bed: m₀ = m_c ^l2_rrler ■ T_ref with the reactor inlet mass flow rn^_rrier in [g/s]

• Fluidized bed: m₀ = m£^l i_rrier ■ T_ref with the reactor inlet mass flow rfic"_rrjer in [g/s] whrein m_C, deposition is the carbon deposition rate [g/s]

\m_c is the carbon mass increase [g]

T_ref is the reactor specific reference residence time [s]

CD_ref is the carbon deposition rate (per reference time unit) in [wt.%].

3. Process according to claim 1 or 2, wherein the hydrocarbon feed is diluted by hydrogen to a volume ratio of H2/C1 + of 1 to 8.

4. Process according to any of claims 1 to 3, wherein said graphitic carbonaceous material has a median pore diameter of 0.01 pm to 0.5 pm, an original D/G ratio of 0.1 to 0.3 and a Lc value of the crystallite sizes of 10 to 70 nm.

5. Process according to any of claims 1 to 4, wherein said graphitic carbonaceous material is synthetic graphitic carbon, synthetic graphites and/or natural graphites and precursors thereof.

6. Process according to any of claims 1 to 5, wherein 10 to 95 vol.-% of said hydrogen-containing product stream is recycled internally to said reaction chamber.

7. Process according to any of claims 1 to 6, wherein the pyrolysis of hydrocarbon is conducted at a temperature ranging from 1100 to 1400°C and a pressure ranging from 2.5 to 15 bar.

8. Process according to any of claims 1 to 7, wherein the bed material is pretreated and passivated with an atmosphere of hydrogen and/or inert gases before starting the production mode of pyrolysis process of hydrocarbons, wherein the time and temperature of said treatment is characterized by the formula T (min °C) = time (min) multiplied by temperature (°C) and T is at least 10000 (min °C) and wherein the temperature is at least 500°C, wherein during said treatment the carbon deposition rate of the pyrolysis process, if any, is below 2 wt.-%, and wherein the atmosphere of said treatment contains 70 to 100 VoL-%, related to the total atmosphere used for the treatment, of hydrogen and/or inert gases and 30 to 0 Vol.-% of gaseous hydrocarbons.

9. Process according to any of claims 1 to 8, wherein the said graphitic carbonaceous material bed is in the form of a moving bed and wherein said graphitic carbonaceous material is guided in countercurrent to the hydrocarbon feed.

10. Process according to any of claims 1 to 9, wherein the hydrogen-containing product stream is taken off via the top of said reaction chamber having a temperature of 10 to 200°C and the said pyrolytic carbon material is taken off via the bottom of said reaction chamber having a temperature of 10 to 200°C.

11 . Process according to any of claims 1 to 10, wherein said bed material in the form of a fixed, fluidized or moving bed has a particle size of 0.3 mm to 8 mm.

12. Process according to any of claims 1 to 11, wherein said solid pyrolytic carbon is post-processed by thermal treatment at a temperature of 2000 to 3000°C in an inert atmosphere.

13. Pyrolytic carbon shell, wherein the outer surface, defined by the outer shell of 5 pm thickness, of said pyrolytic carbon shell has:

(i) D/G ratio 0.1 to 0.8,

(ii) Carbon content 98 to 99.99 wt-%,

(iii) Thickness of the shell from 10 pm to 10 mm,

(iv) Ash content 0 to 2 wt.-%,

(v) Specific surface area 5 to 25 m2/g,

(vi) Median pore diameter from 0.005 to 0.1 pm,

(vii) e-module being in the range of 5 to 35 GPa,

(viii) hardness being in the range of 0.2 to 5 GPa.

14. Pyrolytic carbon shell according to claim 13, wherein the D/G ratio is 0.1 to 0.7.

15. Core-shell particle comprising a core comprising graphitic carbonaceous material having a median pore diameter of 0.005 pm to 1 pm, a D/G ratio of 0.1 to 0.3 and a Lc value of the crystallite sizes of 10 to 70 nm and a shell of pyrolytic carbon obtained from a hydrocarbon pyrolysis having a D/G ratio in the range of 0.1 to 0.8.

16. Core-shell particle according to claim 15, wherein the diameter of the core is from 0.1 mm to 10 mm and the thickness of the shell is from 10 pm to 10 mm.