Catalyst, method for producing catalyst and method for producing solid carbon product

Abstract

The application relates to a catalyst and a method for producing a catalyst for a chemical reaction forming at least a solid carbon product, and a method for producing at least a solid carbon product by a chemical reaction with the catalyst. The catalyst is formed from an inorganic side stream material comprising Fe oxides, in which the inorganic side stream material is pretreated by at least one treatment, selected from a chemical, physical, thermal and / or mechanical treatment, to form a catalyst material, and the catalyst is formed from the catalyst material.

Description

[0001] CATALYST, METHOD FOR PRODUCING CATALYST AND METHOD FOR PRODUCING SOLID CARBON PRODUCT

[0002] FIELD

[0003] The application relates to a catalyst for a chemical reaction forming at least a solid carbon product defined in claim 1. Further, the application relates to a method defined in claim 8 for producing a catalyst for a chemical reaction forming at least a solid carbon product. Further, the application relates to a method defined in claim 17 for producing at least a solid carbon product by a chemical reaction with the catalyst.

[0004] BACKGROUND

[0005] It is known to use different catalysts for forming carbon products. Metal catalysts, such as metal supported catalysts, may be used in the reactions for forming carbon products, e.g. in a thermocatalytic conversion or pyrolysis processes.

[0006] In the iron and steel making processes there are various inorganic side streams. Waste management in the steel industry is a big challenge. Inexpensive low grade iron oxides and iron material or iron based material could be potential catalytic materials. However, these low grades and low cost iron materials are low in methane pyrolysis activity. Cold rolling of iron from a blast furnace is a key process to remove a top layer, i.e. mill scale. The mill scale comprises chips and / or flaky mixture of impurities and low-grade iron oxides. The mill scale typically contains low-grade iron oxides, such as hematite, magnetite and wustite, and other impurities, e.g. Ca, Si, Al, Ni and other impurities. OBJECTIVE

[0007] The obj ective is to disclose a novel type of catalyst for a reaction in which solid carbon products are produced . Further, the obj ective is to disclose a novel type of method for producing the catalyst . Further, the obj ective is to di sclose an improved proces s for thermocatalytic decomposition, e . g . methane decomposition or pyrolysis . Further, the obj ective is to achieve an ef fective process for forming solid carbon products .

[0008] SUMMARY

[0009] The catalyst , method for producing the catalyst and method for producing at least a solid carbon product are characteri zed by what are presented in the claims .

[0010] The catalyst , for a chemical reaction forming at least a solid carbon product , is formed from inorganic side stream material comprising Fe based compounds , such as Fe oxides , in which the inorganic s ide stream material is pretreated by a treatment , selected from a chemical , physical , thermal and / or mechanical treatment, to form a catalyst material . The catalyst may be formed from the catalyst material .

[0011] The method for producing a catalyst for a chemical reaction forming at least a solid carbon product comprises : selecting inorganic side stream material comprising Fe based compounds , such as Fe oxides , pretreating the inorganic side stream material by a treatment, selected from a chemical , physical , thermal and / or mechanical treatment , to form a catalyst material , and forming the catalyst from the catalyst material .

[0012] The method for producing at least a solid carbon product by a chemical reaction with the catalyst comprises arranging a reactant into contact with the catalyst for performing the chemical reaction in a reactor to form the solid carbon product , performing the chemical reaction in the reactor, and recovering at least the solid carbon product.

[0013] DETAILED DESCRIPTION

[0014] The catalyst for a chemical reaction forming at least a solid carbon product, wherein the catalyst is formed from inorganic side stream material comprising at least Fe oxides, in which the inorganic side stream material is pretreated by at least one treatment, e.g. a pretreatment, selected from a chemical, physical, thermal and / or mechanical treatment, to form a catalyst material, and the catalyst is formed from the catalyst material .

[0015] The method for producing a catalyst for a chemical reaction forming at least a solid carbon product, wherein the method comprises: selecting inorganic side stream material comprising at least Fe oxides, pretreating the inorganic side stream material by at least one treatment, e.g. a pretreatment, selected from a chemical, physical, thermal and / or mechanical treatment, to form a catalyst material, and forming the catalyst from the catalyst material. The inorganic side stream material may be pretreated using one or more treatment or treatment step .

[0016] The method for producing at least a solid carbon product by a chemical reaction with the catalyst comprises a) arranging a reactant into contact with the catalyst for performing the chemical reaction in a reactor to form the solid carbon product; b) performing the chemical reaction at a temperature of 550 - 1000 °C in the reactor; and c) recovering at least the solid carbon product.

[0017] In this context, inorganic side stream material, i.e. inorganic raw material, means any inorganic material, inorganic side stream material, residual material, industrial waste material, iron pellets, e.g. fresh iron pellets or a sieved fraction of the pellets, or the like, which comprises at least iron oxides. The inorganic side stream material may comprise several components, and further other Fe based compounds and / or impurities. In one embodiment, the inorganic side stream material further comprises iron hydroxides. In one embodiment, the inorganic side stream material comprises at least iron oxides and iron hydroxides. In one embodiment, the inorganic side stream material comprises hematite, magnetite, wustite or any combination thereof. Hematite comprises at least Fe2O3. Magnetite may comprise Fe3O4, FeO and Fe2O3. Wustite (wuestite) comprises at least FeO. In one embodiment, the inorganic side stream material comprises at least magnetite, wustite or any combination thereof. In one embodiment, the inorganic side stream material comprises magnetite and wustite over 65 wt.%, over 80 wt . % or over 90 wt . % . In one embodiment, the inorganic side stream material comprises magnetite 0.1 - 50 wt.%, in one embodiment 0.1 - 35 wt.%, in one embodiment 0.1 - 27 wt.%, and in one embodiment 0.1 - 25 wt.%. In one embodiment, the inorganic side stream material comprises wustite 50 - 95 wt.%, in one embodiment 60 - 90 wt.%, and in one embodiment 65 - 85 wt.%. In one embodiment, the inorganic side stream material comprises Fe3O3below 25 wt.%, in one embodiment below 20 wt.%, and in one embodiment below 15 wt.%, e.g. 0.1 - 25 wt.%, or 0.1. 20 wt.%, or 0.1 - 15 wt.%. In one embodiment, the inorganic side stream material comprises iron hydroxides. The inorganic side stream material may comprise also Ni, Cu and / or Co, or compounds which contain Ni, Cu and / or Co.

[0018] In one embodiment, the inorganic side stream material is selected from the group consisting of side stream material of iron or steel production, mill scale, acid-pickled iron oxide side stream, secondary dust, mixer slag, mixer wreckage, sludge from blast furnace, sludge from converter, sieve subfraction of iron pellets, ferronickel slag, ladle slag, iron sludge from cobalt production, jarosite, or any combination thereof. The inorganic side stream material, that is used as raw material for producing the catalyst, may further comprise fresh inorganic material, e.g. iron pellets or j arosite .

[0019] In one embodiment, the inorganic side stream material is arranged into the form of particles, balls, flakes, powder, pellets, tablets, spheres, rods, plates, agglomerates or any combination thereof, preferably before the treatment, such as activation treatment.

[0020] The inorganic side stream material is treated by the chemical, physical, thermal and / or mechanical treatment. In one embodiment, the inorganic side stream material is treated by at least one of the chemical, physical, thermal and mechanical treatment. In one embodiment, the inorganic side stream material is treated by at least one chemical treatment. In one embodiment, the inorganic side stream material is treated by at least one physical treatment. In one embodiment, the inorganic side stream material is treated by at least one thermal treatment. In one embodiment, the inorganic side stream material is treated by at least one mechanical treatment. In one embodiment, the inorganic side stream material is treated by at least one chemical and physical treatment. In one embodiment, the inorganic side stream material is treated by at least one chemical and thermal treatment. In one embodiment, the inorganic side stream material is treated by at least one chemical and mechanical treatment. In one embodiment, the inorganic side stream material is treated by at least one physical and thermal treatment. In one embodiment, the inorganic side stream material is treated by at least one physical and mechanical treatment. In one embodiment, the inorganic side stream material is treated by at least one thermal and mechanical treatment. In one embodiment, the inorganic side stream material is treated by at least one chemical, physical, thermal and mechanical treatment. When the inorganic side stream material is pretreated by the chemical, physical, thermal and / or mechanical treatment, the catalyst formed from the pretreated material is active at moderate reaction temperatures, e.g. 550 - 1000 °C or in one embodiment 700 - 900 °C, in the thermocatalytic decomposition process, and the catalyst performance can be enhanced in elevated decomposition temperatures.

[0021] In one embodiment, the inorganic side stream material is treated at least by the chemical treatment. In one embodiment, the inorganic side stream material is treated by the chemical treatment selected from the group consisting of acid treatment, acid digestion, addition of metal promoter, treatment with alkali, treatment with salt, and any combination thereof. In one embodiment, the acid treatment is selected from an acid dissolution or acid precipitation. In one embodiment, the inorganic side stream material is treated by the treatment with alkali using an alkali. The alkali may comprise any suitable alkali, base compound or any combination thereof. In one embodiment, the inorganic side stream material is treated by the treatment with salt using a salt component. The salt component may comprise one or more salt compound(s) , e.g. NaCl . In the addition of metal promoter, one or more metals or metal compounds, e.g. metal oxides, may be added to the inorganic side stream material, or alternatively to the catalyst material. In this context, metal promoter means any metal promoter, dopant, additive or the like. By means of the addition of metal promoter a carbon morphology, e.g. in the solid carbon product, can be modified by adding different metals . In one embodiment, the inorganic side stream material is treated by the acid treatment, e.g. acid dissolution and / or acid precipitation. By means of the acid dissolution and precipitation, an isolation of Fe oxides can be improved, and further impurities can be leached out and / or reducibility can be enhanced at low temperatures. In the acid treatment, the inorganic side stream material is treated using an acid. The acid may comprise one or more acid(s) or acid compound (s) . In one embodiment, HC1, HNO3, HCOOH, CH3COOH, H2O2, H2SO4, H3PO4, or other suitable acid or any combination thereof is used as acid in the acid treatment. In one embodiment, HC1, HNO3 or HCOOH is used as acid in the acid treatment. In one embodiment, HC1 is used as acid in the acid dissolution and precipitation. In one embodiment, the acid treatment, such as the acid dissolution and precipitation, are carried out at a temperature of 25 - 100 °C, in one embodiment at a temperature of 50 - 80 °C, and in one embodiment at a temperature of 55 - 65 °C.

[0022] In one embodiment, the inorganic side stream material is treated at least by the thermal treatment. In one embodiment, the thermal treatment is performed using heat. In one embodiment, the inorganic side stream material is treated by the thermal treatment, which is selected from the group consisting of sintering, calcination, reduction, or any combination thereof. In one embodiment, the inorganic side stream material is treated at least by the reduction. In one embodiment, the inorganic side stream material is treated at a temperature of 100 - 1000 °C, in one embodiment at a temperature of 600 - 900 °C in one embodiment at a temperature of 120 - 600 °C, and in one embodiment at a temperature of 130 - 400 °C.

[0023] In one embodiment, the inorganic side stream material is treated at least by the physical treatment. In one embodiment, the inorganic side stream material is treated by the physical treatment, which is selected from the group consisting of a steam activation, air activation, carbon dioxide activation, tempering, or any combination thereof . In one embodiment, the inorganic side stream material is treated by the physical treatment selected from the group consisting of steam activation, carbon dioxide activation, tempering, and any combination thereof . In one embodiment , the inorganic side stream material is treated by the air activation . In one embodiment , the inorganic s ide stream material is treated at least by the carbon dioxide activation, and the carbon dioxide activation is performed under supercritical conditions . In one embodiment , to get carbon dioxide phase into the supercritical region, temperature is at least 31 . 1 ° C or above and pressure is at least 73 . 8 bar or above . In one embodiment, the inorganic side stream material is treated at least by the steam activation . In the steam activation, the inorganic s ide stream material is treated by steam. In one embodiment , the inorganic side stream material is treated at a temperature of 100 - 800 ° C, in one embodiment 400 - 800 °C, or in one embodiment 150 - 350 ° C . In one embodiment, the inorganic side stream material is treated at a temperature of 130 - 180 ° C, in one embodiment at a temperature of 180 - 220 ° C, in one embodiment at a temperature of 220 - 280 °C, and in one embodiment at a temperature of 280 - 300 °C, in the steam activation . In one embodiment , a separate calcination is not needed, if the steam activation is performed at a high temperature , e . g . at 400 - 1000 °C or 600 - 900 °C . Then the calcination may be achieved simultaneously with the steam activation . In one embodiment, heat for the steam activation or steam generation is recirculated from a chemical reaction, where a solid carbon product and / or hydrogen are formed, e . g . from thermocatalytic decomposition . In one embodiment , heat for the steam activation or steam generation is supplied from a hydrogen combustion. In one embodiment, heat and / or steam for the steam activation is supplied from a reaction of hydrogen and air. In one embodiment, the inorganic side stream material is treated at least by the tempering. In the tempering, the inorganic side stream material is treated by heat. In one embodiment, the particles of the catalyst material are heated in air to form a red-hot material, and after that the particles are dropped into water or water is injected onto the particles. Then the core of the particles remains metal, and an active layer is formed onto the surface of the particles. By means of the physical treatment, the activity of the catalyst can be enhanced, and carbon and hydrogen yields can be improved.

[0024] In one embodiment, the inorganic side stream material is treated at least by the mechanical treatment. In one embodiment, the inorganic side stream material is treated by the mechanical treatment selected from the group consisting of milling, ball milling, granulation, and any combination thereof. In one embodiment, the inorganic side stream material is treated at least by the milling, e.g. ball milling, jet milling, pan milling or vibro milling. In one embodiment, the inorganic side stream material is treated at least by the ball milling. In one embodiment, the ball milling is carried out with balls, such as milling balls, e.g. zirconia balls. In one embodiment, ball diameter of the balls is 0.1 - 20 mm, in one embodiment 2 - 12 mm. In one embodiment, particle size of the ball milled material is 100 - 1000 pm after the ball milling. In one embodiment, the size of the ball milled material is 100 - 3000 pm after the ball milling. In one embodiment, particle size of the ball milled material is 100 - 299 pm after the ball milling. In one embodiment, particle size of the ball milled material is 300 - 499 pm after the ball milling. In one embodiment, particle size of the ball milled material is 500 - 700 pm after the ball milling. By means of the ball milling the catalyst material, and thus the catalyst, can be made more uniform, active and stable, and the surface can be re-structured due to shear stress and friction generated during the ball milling. In one embodiment, the inorganic side stream material is treated at least by the granulation. In one embodiment, the granulation is carried out in a granulation device, an agglomeration device or the like to form granulated material. In one embodiment, a binder is used in the granulation. In one embodiment, the granulated material, e.g. granules, is dried and / or calcined after the granulation.

[0025] In one embodiment, heat is used during the treatment .

[0026] In one embodiment, the inorganic side stream material is in the form of particles, e.g. pellets, balls, powder, tablets, spheres, agglomerates or flakes. In one embodiment, the inorganic side stream material comprises a particle mixture. In one embodiment, the inorganic side stream material is the particle mixture. The particle mixture may contain different particles, or different pelletized particles and mixed particles, or different pelletized particles. In one embodiment, the inorganic side stream material is arranged into the form of particles and / or pelletized particles before the treatment. In one embodiment, the inorganic side stream material has particle size of 100 - 3000 pm before the treatment. In one embodiment, the inorganic side stream material has particle size of 100 - 700 pm, in one embodiment 100 - 300 pm, in one embodiment 300 - 500 pm, and in one embodiment 500 - 700 pm before the treatment. In one embodiment, the inorganic side stream material has particle size of 700 - 3000 pm before the treatment.

[0027] In one embodiment, the inorganic side stream material is dried before the treatment. In one embodiment, the inorganic side stream material is heated before the treatment . In one embodiment , the inorganic side stream material is pre-calcined .

[0028] In one embodiment, the inorganic side stream material and / or the catalyst material , e . g . pretreated inorganic side stream material , is dried and calcined . In one embodiment, the inorganic side stream material and / or the catalyst material is dried and calcined at a temperature of 200 - 1000 °C, in one embodiment 350 - 950 °C, and in one embodiment 550 - 900 °C . In one embodiment , the inorganic side stream material and / or the catalyst material is dried before the calcination . In one embodiment, the inorganic side stream material and / or the catalyst material is dried during the calcination or in the beginning of the calcination . In one embodiment, the drying may be carried out at a temperature of 70 - 300 °C, in one embodiment 70 - 200 ° C, in one embodiment 80 - 95 °C, e . g . about 90 °C .

[0029] In one embodiment, the inorganic side stream material and / or the catalyst material , e . g . pretreated inorganic side stream material , is calcined and / or reduced in the treatment, such as pretreatment , or after the treatment or at least one step of the treatment . In one embodiment, the material is calcined . In one embodiment , the material is reduced . In one embodiment , the material is calcined and reduced . In one embodiment, the material is reduced after the calcination . In one embodiment , the material is reduced under H2 flow . In one embodiment, Fe oxides may be reduced to form Fe metal or metallic crystals in the reduction . In one embodiment , the calcination is carried out at a temperature of 600 - 1000 °C, in one embodiment at a temperature of 700 - 920 °C, and in one embodiment at a temperature of 850 - 920 °C . In one embodiment, the reduction is carried out at a temperature of 500 - 950 ° C, in one at a temperature of 600 - 920 ° C, and in one embodiment at a temperature of 700 - 900 °C. In one embodiment, Fe oxides may be reduced to form Fe metal or metallic crystals in the reduction.

[0030] In one embodiment, a promoter, e.g. catalytic agent or co-catalyst, is added to the inorganic side stream material or catalyst material to form the catalyst. In this context, the promoter means any promoter, catalytic agent, dopant, additive, secondary metal or bimetallic agent, which may be added to the inorganic side stream material or catalyst material. The promoter may be formed of one or more components. In one embodiment, the promoter comprises a catalytically active agent, e.g. metal (s) or metal oxide (s) , preferably at least one catalytically active agent. In one embodiment, the promoter contains a catalytically active agent, e.g. metal (s) or metal oxide (s) , and a carrier material, e.g. Mg-, A1-, Zn-based carrier material. In one embodiment, the promoter consists of the catalytically active agent. In one embodiment, the promoter comprises the catalytically active agent which is selected from the group consisting of nickel, copper, molybdenum, magnesium, zinc, aluminium, titanium, cobalt, manganese, chromium, silicon, boron, platinum, palladium, carbon, and an oxide thereof, and any combination thereof. In one embodiment, the promoter comprises Ni, Cu, Ni-Cu, MgO, ZnO, MnC>2, CeC>2, MoO or any combination thereof. In one embodiment, the promoter comprises at least Ni, Cu or Ni-Cu metals. In one embodiment, the promoter, comprising Ni, Cu, Mg, Zn, Mn, Ce, Mo, their oxide or a combination thereof, is added to the inorganic side stream material or catalyst material to form the catalyst. In one embodiment, the promoter consists of Ni, Cu, or a combination thereof.

[0031] In one embodiment, the promoter is added to the inorganic side stream material and / or the catalyst material. In one embodiment, the promoter is added to the inorganic side stream material. In one embodiment, the promoter is added to the inorganic side stream material by the addition of metal promoter in the treatment, such as pretreatment. In one embodiment, the promoter is added to the catalyst material. In one embodiment, the promoter is arranged onto a surface of the catalyst, where the chemical reaction can be carried out. In one embodiment, the method further comprises: adding the promoter to the inorganic side stream material to form the catalyst. In one embodiment, the method further comprises: adding the promoter to the catalyst material to form the catalyst. By means of the addition of the promoters, e.g. Ni and Cu, reduction of Fe oxides and / or Fe dispersion can be improved at low temperatures. Further, carbon morphology may be modified by adding the promoter ( s ) .

[0032] In one embodiment, the catalyst is produced from the inorganic side stream material, e.g. mill scale. The inorganic side stream material is in the form of particles with particle size of 100 - 3000 pm, e.g. after milling. The inorganic side stream material is dried and calcined, and the promoter, e.g. Ni-Cu, is added to the inorganic side stream material to form the catalyst material. Alternatively, the inorganic side stream material is dried, calcined and reduced under H2 flow, and the promoter, e.g. Ni-Cu, is added to the inorganic side stream material to form the catalyst material .

[0033] In one embodiment, the catalyst is produced from the inorganic side stream material, e.g. mill scale. The inorganic side stream material is treated by the acid treatment, e.g. acid dissolution and / or acid precipitation, using an acid. In one embodiment, HC1, HNO3 or HCOOH is used as acid in the acid treatment. The promoter, e.g. Ni, Cu or Ni-Cu, may be added to the inorganic side stream material to form the catalyst material. Further, the inorganic side stream material may be dried and calcined, or dried, calcined and reduced, e.g. under H2 flow.

[0034] In one embodiment, the catalyst is produced from the inorganic side stream material, e.g. mill scale. The inorganic side stream material is treated by a steam activation using steam, e.g. at a temperature of 100 - 400 °C. The promoter, e.g. Ni, Cu or Ni-Cu, may be added to the inorganic side stream material to form the catalyst material. Further, the inorganic side stream material may be dried and calcined, or dried, calcined and reduced, e.g. under H2 flow.

[0035] In one embodiment, the catalyst is produced from the inorganic side stream material, e.g. mill scale. The inorganic side stream material is treated by a ball milling using balls, e.g. in which ball diameter of the balls is 0.1 - 20 mm. The promoter, e.g. Ni, Cu or Ni-Cu, may be added to the inorganic side stream material to form the catalyst material. Further, the inorganic side stream material may be dried and calcined, or dried, calcined and reduced, e.g. under H2 flow.

[0036] In one embodiment, a particle size of the catalyst material is 100 - 5000 pm. In one embodiment, a particle size of the catalyst material is 100 - 3000 pm. In one embodiment, a particle size of the catalyst material is 3000 - 5000 pm. In one embodiment, a particle size of the catalyst material is 200 - 800 pm.

[0037] The catalyst is formed from the catalyst material. The catalyst may comprise a desired shape or structure .

[0038] The solid carbon product is formed in the process. The solid carbon product comprises at least carbon, especially an allotrope of carbon. Preferably, the carbon product is formed as the reaction product in the solid form. In one embodiment, the solid carbon product comprises an allotrope of carbon and / or graphitic structure, and the allotrope and / or graphitic structure comprises carbon nanofibers, carbon nanotubes, single wall carbon nanotubes, multiwalled carbon nanotubes, carbon nano onions, carbon nano shells, carbon micro shells, carbon coils, amorphous carbon, graphene, graphite fibers, graphite, or any combination thereof. In one embodiment, the allotrope and / or graphitic structure comprises carbon nanofibers and / or carbon nanotubes. In one embodiment, the allotrope of the carbon product is a mixture of the allotropes. The allotrope of the carbon product may contain also other graphitic type carbon and / or metal or metal oxide impurities. When the promoters, e.g. metal or metal oxides, are added to the catalyst material, different types of the carbon can be produced. Further, the pretreatments may also affect the carbon morphology.

[0039] In one embodiment, the chemical reaction is selected from the group consisting of a methane splitting, catalysed methane splitting, catalysed pyrolysis, catalysed hydrocarbon pyrolysis, catalysed methane pyrolysis, catalysed biomethane pyrolysis, catalysed biomethane splitting, catalysed biogas pyrolysis, catalytic hydrocarbon decomposition, catalytic biobased hydrocarbon decomposition, catalytic methane decomposition, thermocatalytic decomposition, thermocatalytic methane decomposition, chemical vapor deposition, or any combination thereof. In one embodiment, the chemical reaction is the thermocatalytic decomposition.

[0040] In one embodiment, hydrogen is formed in the chemical reaction, and the hydrogen is recovered from the reactor. In one embodiment, the method further comprising producing hydrogen in the reactor.

[0041] Preferably, the chemical reaction is carried out by the catalyst in the reactor, preferably inside the reactor. In this context, the reactor may be any reactor, chamber or space where the chemical reaction can be carried out. In one embodiment, the reactor is selected from the group consisting of a pyrolysis reactor, fluidized reactor, fixed reactor, fixed bed reactor, rotary kiln reactor or any combination thereof. In one embodiment, the reactor is a fluid bed reactor, e.g. fluidized reactor, or a rotary kiln reactor.

[0042] The chemical reaction may be performed at a temperature of 550 - 1000 °C in the reactor. In one embodiment, the chemical reaction is performed at a reaction temperature of between 600 - 900 °C, in one embodiment 750 - 850 °C. In one embodiment, the chemical reaction is performed at a pressure between 0 - 5 bars and / or at a temperature between 550 - 1000 °C, e.g. 600 - 900 °C. In one embodiment, the chemical reaction is performed under the atmospheric pressure. In one embodiment, the chemical reaction is performed under the pressure of between 0 - 5 bars. In one embodiment, the contact time of the reactant with the catalyst is selected based on the reactant and the catalyst.

[0043] In one embodiment, the chemical reaction is the reaction, in which the hydrocarbon is treated, and the hydrocarbon is selected from the group of Ci-io-alkanes , such as methane and ethane, C2-io_alkenes and C2-io_al- kynes, or a mixture of hydrocarbons. Preferably, the reactant is fed to the reactor and the chemical reaction is performed in the reactor, and at least carbon is formed, and it can be recovered. Preferably, the reactant is arranged to contact with the catalyst in the reactor. In this context, the reactant means any suitable reactant, which can be treated in the process. In one embodiment, the reactant is a hydrocarbon selected from the group of Ci-io-alkanes, such as methane and ethane, C2-io_alkenes , and C2-io_alkynes, or any combination thereof. In one embodiment, the reactant comprises at least natural gas, biogas, methane and / or biomethane.

[0044] Raw material, such as side stream material, e.g. inorganic side stream material, may be pretreated by an acid treatment or other chemical treatment for forming a catalyst material. The side stream material may be any side stream material, residual material, industrial waste material or the like. The inorganic side stream material may mean any inorganic side stream material as defined above. In one embodiment, the raw material is treated at least by the acid treatment, e.g. acid dissolution and precipitation. In the acid treatment, the raw material is treated by an acid, e.g. HC1, HNO3, HCOOH, CH3COOH, H2O2, H2SO4, H3PO4, or other suitable acid or any combinations thereof, at a suitable temperature. In an alternative embodiment, the raw material is treated by the treatment with alkali using an alkali or by the treatment with salt using a salt component, e.g. NaCl. In one embodiment, the raw material is treated by the treatment selected from the acid treatment, treatment with alkali and / or treatment with salt. In one embodiment, the raw material is treated at a temperature of 25

[0045] - 100 °C, in one embodiment at a temperature of 50 - 80 °C. Preferably, the promoter, as defined above, may be added to the material to form the catalyst material. By means of the acid dissolution and precipitation, an isolation of Fe oxides can be improved, and further impurities can be leached out and / or reducibility can be enhanced at low temperatures. Further, by means of the addition of the promoters, e.g. Ni and Cu, reduction of Fe oxides and / or Fe dispersion can be improved at low temperatures. Further, the activity of the catalyst can be enhanced, and carbon and hydrogen yields can be improved in the process. The pretreated, i.e. acid treated, material can be used as a catalyst in a ther- mocatalytic decomposition, e.g. at a temperature of 550

[0046] - 1000 °C, in one embodiment at 700 - 800 °C, for forming at least a solid carbon product, and further hydrogen.

[0047] Raw material, such as side stream material, e.g. inorganic side stream material, may be pretreated by a ball milling for forming a catalyst material. The side stream material may be any side stream material, residual material, industrial waste material or the like. The inorganic side stream material may mean any inorganic side stream material as defined above. In one embodiment, the ball milling is carried out using balls. In one embodiment, the ball milling is carried out using zirconia balls. In one embodiment, ball diameter of the balls is 0.1 - 20 mm, in one embodiment 2 - 12 mm. In one embodiment, particle size of the ball milled material is 100 - 3000 pm after the ball milling. In one embodiment, particle size of the ball milled material is 100 - 299 pm after the ball milling. In one embodiment, particle size of the ball milled material is 300 - 499 pm after the ball milling. In one embodiment, particle size of the ball milled material is 500 - 700 pm after the ball milling. In one embodiment, the promoter, as defined above, is added to the material to form the catalyst material. By means of the ball milling the catalyst material can be made more uniform, active and stable, and the surface can be re-structured due to shear stress and friction generated during the ball milling. The pretreated, i.e. ball milled, material can be used as a catalyst in a thermocatalytic decomposition, e.g. at a temperature of 550 - 1000 °C, in one embodiment at 700 - 900 °C, for forming at least a solid carbon product, and further hydrogen.

[0048] Raw material, such as side stream material, e.g. inorganic side stream material, may be pretreated by a granulation for forming a catalyst material. The side stream material may be any side stream material, residual material, industrial waste material or the like. The inorganic side stream material may mean any inorganic side stream material as defined above. In one embodiment, the granulation is carried out in a granulation device, an agglomeration device or the like to form granules, i.e. granulated material. In one embodiment, the granulation is carried out in a granulator drum to form the granules. In one embodiment, a binder is added. In one embodiment, the granulated material, such as granules, is dried and calcined after the granulation. In one embodiment, the particle size of the granules may be between 0.1 - 2.5 mm. The granulated material can be used as a catalyst in a thermocatalytic decomposition, e.g. at a temperature of 550 - 1000 °C, in one embodiment at 700 - 900 °C, for forming at least a solid carbon product, and further hydrogen.

[0049] Raw material, such as side stream material, e.g. inorganic side stream material, may be pretreated by a steam activation for forming a catalyst material. The side stream material may be any side stream material, residual material, industrial waste material or the like. The inorganic side stream material may mean any inorganic side stream material as defined above. In one embodiment, the raw material comprises iron, e.g. low-grade iron, and / or iron oxides. In one embodiment, the raw material is treated at least by the steam activation. In the steam activation, the raw material is treated by steam. In one embodiment, the raw material is treated at a temperature of 100 - 400 °C, in one embodiment at a temperature of 220 - 280 °C, and in one embodiment at a temperature of 230 - 270 °C. In one embodiment, a calcination is performed after the steam activation. In one embodiment, the raw material is treated at a temperature of 100 - 1000 °C, e.g. at a temperature of 400

[0050] - 800 °C, and in one embodiment at a temperature of 600

[0051] - 900 °C, in the steam activation. Then, a calcination may be performed during the steam activation, when high temperatures are used. In one embodiment, the promoter, as defined above, is added to the material to form the catalyst material. By means of the steam activation, an activity of the catalyst can be enhanced, and carbon and hydrogen yields can be improved. The pretreated, i.e. steam activated, material can be used as a catalyst in a thermocatalytic decomposition, e.g. at a temperature of 550 - 1000 °C, in one embodiment at 700 - 900 °C, for forming at least a solid carbon product, and further hydrogen .

[0052] In one embodiment, the catalyst is used in a methane splitting, catalysed methane splitting, catalysed pyrolysis, catalysed hydrocarbon pyrolysis, catalysed methane pyrolysis, catalysed biomethane pyrolysis, catalysed biomethane splitting, catalysed biogas pyrolysis, catalytic hydrocarbon decomposition, catalytic biobased hydrocarbon decomposition, catalytic methane decomposition, thermocatalytic decomposition, thermocatalytic methane decomposition, chemical vapor deposition, or any combination thereof. In one embodiment, the catalyst is used in a reactor, vertical reactor, tube reactor, fixed reactor, fixed bed reactor, pyrolysis reactor, fluidized reactor, rotary kiln reactor or any combination thereof. The reactor may be a batch reactor or a continuous reactor. In one embodiment, the reactor is a batch rotary kiln reactor or a continuous rotary kiln reactor.

[0053] Thanks to the invention an effective process can be provided to produce solid carbon products and hydrogen. When the inorganic side stream material is treated by the pretreatment, the activity of the catalyst can be increased, and the catalyst is active already at low temperatures, e.g. at 700 - 850 °C. The carbon and hydrogen yield and methane conversion can be increased. Further, the carbon formation and allotropes may be modified. The carbon product having high purity may be achieved. Further, the pretreatment modifies the structure of the inorganic side stream material and / or physico-chemical properties, e.g. surface area, diffusion, dispersion, chemisorption, reduction profile and other properties. The Fe oxide based catalysts are cheap, environmentally friendly and sustainable.

[0054] The invention offers a possibility to achieve the carbon product and hydrogen with good properties easily. Further, efficiency can be improved in the ther- mocatalytic decomposition process, e.g. methane splitting. Further, utilizing side stream materials environmental impacts can be solved, i.e. waste material can be utilized and landfill waste can be reduced, and cost- effective catalyst components can be used in the production of synthetic graphite. Further, lower carbon footprint can be achieved, when the side stream materials are used to form catalysts. Further, the catalyst may be regenerated, recycled and / or reused.

[0055] BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The accompanying drawings, which are included to provide a further understanding of the invention and constitute a part of this specification, illustrate some embodiments of the invention and together with the description help to explain the principle of the invention. In the drawings:

[0057] Fig. 1 shows test results of the catalysts,

[0058] Fig. 2 shows another test results of the catalysts, and

[0059] Fig. 3 shows another test results of the catalysts.

[0060] EXAMPLES

[0061] The catalyst is produced from inorganic side stream material. The inorganic side stream material is treated by a pretreatment to form a catalyst material, and the catalyst is formed from the catalyst material. For example, Fe oxide based mill scale and / or other Fe oxide based side stream material may be used as the inorganic side stream material. Preferably, the inorganic side stream material comprises Fe2Os below 25 wt . % .

[0062] The inorganic side stream material is treated by a chemical, physical, thermal and / or mechanical treatment, which may be selected from the group consisting of an acid treatment, alkali treatment, salt treatment, promoter addition, steam activation, carbon dioxide activation, tempering, ball milling, granulation, or any combination thereof.

[0063] According to an example, a promoter is added to the inorganic side stream material or catalyst material to form the catalyst. The promoter comprises metal (s) and / or metal oxide (s) , e.g. Ni, Cu, Mg, Zn, Mn, Ce, Mo or their combinations.

[0064] The catalyst is formed from the catalyst material. The catalyst can be used in the chemical reaction for forming a solid carbon product, preferably comprising an allotrope or allotropes of the carbon. A hydrocarbon reactant, e.g. methane or other hydrocarbon, is arranged into contact with the catalyst for performing the chemical reaction in a reactor, e.g. fluid bed reactor, rotary kiln or other suitable reactor, to form the carbon product. According to an example, the chemical reaction is performed at a temperature of 600 - 1000 °C in the reactor, and at least the solid carbon product is recovered.

[0065] Example 1

[0066] In this example, the catalyst was formed from inorganic side stream material, which is mill scale material, comprising Fe oxides. The inorganic side stream material was treated by a pretreatment, selected from chemical, physical, thermal and / or mechanical pretreatment, to modify the material in order to form an improved catalyst material. The promoter may be added to the inorganic side stream material or the catalyst material, i.e. pretreated inorganic side stream material.

[0067] According to an example, the pretreated inorganic side stream material is dried and calcined, e.g. at a temperature of 800 - 950 °C, and / or reduced, e.g. at a temperature of 700 - 900 °C.

[0068] The pretreated inorganic side stream material and the catalyst material can be used as the catalyst in a thermocatalytic decomposition of methane at a temperature of 600 - 1000 °C for forming a solid carbon product and hydrogen. The carbon yield and methane conversion can be increased using the pretreatment and / or the addition of the promoter. Further, the pretreatment modifies the structure of the inorganic side stream material, e.g. reactivity and surface area can be increased in the surface structure.

[0069] Example 2

[0070] In this example, the catalyst was formed from the material of Example 1.

[0071] The inorganic side stream material was pretreated by an acid treatment, i.e. by an acid dissolution and precipitation. HC1 was used as acid in the acid treatment. The promoter, i.e. Ni-promoter, may be added to the inorganic side stream material.

[0072] It was observed that the acid treated and Ni- promoted catalyst gave the high carbon yield (gC / gCat) compared to an untreated catalyst, when the treated material was used as the catalyst in the thermocatalytic decomposition of methane, according to example 1, at a temperature within 650 - 850 °C in a mid-scale reactor. Further, the treated material reduced operating reaction temperature, and preferably reduced the temperature window from 1000 °C to and around 750 °C. Example 3

[0073] In this example, the catalyst was formed from the material of Example 1.

[0074] The inorganic side stream material was pretreated by a ball milling. The ball milling was carried out using zirconia balls. The particle size of the ball milled material was 500 - 700 pm.

[0075] It was observed that the ball milled samples were more uniform and more active, and further more stable, than unmilled samples, when the material was used as the catalyst in the thermocatalytic decomposition of methane, as defined in example 1. It was observed that carbon yield, e.g. nearly 2.5 times of carbon yield, and H2 concentration can be increased, when the ball milled material was used.

[0076] Example 4

[0077] In this example, the catalyst was formed from the material of Example 1.

[0078] The inorganic side stream material was pretreated by a steam activation. In the steam activation, the iron based material was treated by steam at a temperature of about 250 °C.

[0079] It was observed that the steam activated catalyst was more active than untreated catalyst, when the steam activated material was used as the catalyst in the thermocatalytic decomposition of methane, according to example 1, at a temperature of about 850 °C in a midscale reactor. Further, the carbon yield per gram of catalyst (gC / g Cat) was higher, even 7.5 times better, when the steam activated material was used as the catalyst.

[0080] Example 5

[0081] In this example, the catalyst was formed from the material of Example 1. The inorganic side stream material was pretreated by a granulation . In the granulation, the iron based material was treated in a granulator drum to form granulated material . The granulated material was dried and calcined at an elevated temperature . The particle size of the treated material was between 100 - 2000 pm .

[0082] Example 6

[0083] In this example , the catalyst was formed from inorganic side stream material , which is mill scale material , comprising Fe oxides .

[0084] A part of the inorganic side stream material samples was pretreated by an acid treatment . After the acid treating the samples were calcined . A part of the inorganic side stream material samples was treated by adding a metal promoter . The inorganic side stream material was impregnated using the promoter .

[0085] The treated material was used as the catalyst in the thermocatalytic decomposition of methane at a temperature within 800 - 850 ° C .

[0086] The test results are shown in Fig . 1 , in which the samples are :

[0087] • SSH- 0 . 5HA - acid treated with 0 . 5 M acid

[0088] • SSH- 1HA - acid treated with 1 M acid

[0089] • SSH-4HA - acid treated with 4 M acid

[0090] • SSH- 6HA - acid treated with 6 M acid

[0091] • SSH- 8HA - acid treated with 8 M acid

[0092] • SSH-2C - treated by impregnating 2 wt-% promotor metal

[0093] • SSH- 10C - treated by impregnating 10 wt-% promotor metal

[0094] • SSH-2N - treated by impregnating 2 wt-% promotor metal

[0095] • SSH- 10N - treated by impregnating 10 wt-% promotor metal

[0096] • SSH-2NA - acid treated with 2 M acid It was observed that the acid treated catalyst gave the high carbon yield (gC / gCat) , when the treated material was used as the catalyst in the thermocatalytic decomposition of methane. Further, it was observed from the test that the acid treated catalyst gave the high carbon yield compared to an untreated catalyst.

[0097] Example 7

[0098] In this example, the catalyst was formed from the inorganic side stream material, which is mill scale material, comprising Fe oxides.

[0099] The inorganic side stream material samples were pretreated by a ball milling. The ball milling was carried out using balls. Further, a comparative test sample (test 1) was prepared, and the test results (tests 2-5) of the samples were compared to the results of the comparative test sample. All the samples were reduced at a reduction temperature of 800 °C. The treated material was used as the catalyst in the thermocatalytic decomposition of methane at a temperature of about 850 °C.

[0100] The test results are shown in Fig. 2, in which the samples are: test 1, 10 g unmilled mill scale material, particle size 0.1 - 3 mm ; test 2, 10 g ball milled mill scale material, particle size 0.1 - 3 mm; test 3, 10 g ball milled mill scale material, particle size 0.1 - 3 mm; test 4, 5 g ball milled mill scale material, particle size 0.1 - 3 mm; and test 5, 5 g ball milled mill scale material, particle size 0.1 - 3 mm.

[0101] It was observed that carbon yield can be increased, when the ball milled material was used. Example 8

[0102] In this example, the catalyst material (SSH mix) was formed from inorganic side stream material, which is mill scale material, comprising Fe oxides.

[0103] A part of the inorganic side stream material samples was calcined and reduced. A part of the inorganic side stream material samples was only reduced. The reduction was carried out at 650 °C - 950 °C, and the reduction time was 300 min in these runs.

[0104] The treated catalyst material was used as the catalyst in the thermocatalytic decomposition of methane at a temperature within 800 - 850 °C in a pilot reactor.

[0105] The test results are shown in Fig. 3.

[0106] It was observed that the reduction gave the high total carbon amount (g) and carbon yield (gC / gCat) , when the treated catalyst material was used as the catalyst in the thermocatalytic decomposition of methane. Further, it was observed from the test that the treated catalyst material, which was only reduced, gave the higher total carbon amount and carbon yield compared to the catalyst material, which was calcined and reduced.

[0107] The catalyst and method are suitable in different embodiments for using in different processes where carbon is formed. Further, the invention is suitable in different embodiments for producing carbon products and other products, such as hydrogen.

[0108] The invention is not limited merely to the examples referred to above; instead, many variations are possible within the scope of the inventive idea defined by the claims.

Claims

CLAIMS1 . A catalyst for a chemical reaction forming at least a solid carbon product, wherein the catalyst is formed from an inorganic side stream material comprising Fe oxides, in which the inorganic side stream material is pretreated by at least one treatment, selected from a chemical, physical, thermal and / or mechanical treatment, to form a catalyst material, and the catalyst is formed from the catalyst material.

2. The catalyst according to claim 1, wherein a particle size of the catalyst material is 100 - 5000 pm.

3. The catalyst according to claim 1 or 2, wherein the inorganic side stream material comprises hematite, magnetite, wustite or any combination thereof.

4. The catalyst according to any one of claims 1 to 3, wherein the inorganic side stream material comprises Fe2C>3 below 25 wt . % .

5. The catalyst according to any one of claims 1 to 4, wherein the inorganic side stream material is selected from the group consisting of side stream material of iron or steel production, mill scale, acid- pickled iron oxide side stream, secondary dust, mixer slag, mixer wreckage, sludge from blast furnace, sludge from converter, ladle slag, sieve subfraction of iron pellets, ferronickel slag, iron sludge from cobalt production, jarosite, or any combination thereof.

6. The catalyst according to any one of claims 1 to 5, wherein the inorganic side stream material is dried and calcined.

7. The catalyst according to any one of claims 1 to 6, wherein a promoter comprising Ni, Cu, Mo, Co or a combination thereof, is added to the catalyst material to form the catalyst.8 . A method for producing a catalyst for a chemical reaction forming at least a solid carbon product , wherein the method comprises : selecting an inorganic side stream material comprising Fe oxides , pretreating the inorganic side stream material by at least one treatment, selected from a chemical , physical , thermal and / or mechanical treatment, to form a catalyst material , and forming the catalyst from the catalyst material .9 . The method according to claim 8 , wherein the inorganic side stream material is treated by the chemical treatment selected from the group consisting of acid treatment, acid digestion, addition of metal promoter, treatment with alkali , treatment with salt, and any combination thereof .10 . The method according to claim 8 or 9 , wherein the inorganic side stream material is treated by the physical treatment selected from the group consisting of steam activation, carbon dioxide activation, tempering, and any combination thereof .11 . The method according to any one o f claims 8 to 10 , wherein the inorganic side stream material is treated by the mechanical treatment selected from the group consisting of milling, ball milling, granulation, and any combination thereof .12 . The method according to any one of claims 8 to 11 , wherein the inorganic side stream material is treated by the thermal treatment selected from the group consisting of sintering, calcination, reduction, and any combination thereof .13 . The method according to any one of claims 8 to 12 , wherein the inorganic side stream material is dried and calcined at a temperature of 200 - 1000 ° C .14 . The method according to any one of claims 8 to 13 , wherein the inorganic side stream material is selected from the group consisting of side streammaterial of iron or steel production, mill scale, acid- pickled iron oxide side stream, secondary dust, mixer slag, mixer wreckage, sludge from blast furnace, sludge from converter, ladle slag, sieve subfraction of iron pellets, ferronickel slag, iron sludge from cobalt production, jarosite, or any combination thereof.

15. The method according to any one of claims 8 to 14, wherein the inorganic side stream material comprises Fe2Os below 25 wt . % .

16. The method according to any one of claims 8 to 15, wherein the method further comprises: adding a promoter comprising Ni, Cu, Mo, Co or a combination thereof, to the catalyst material to form the catalyst.

17. A method for producing at least a solid carbon product by a chemical reaction with the catalyst according to any preceding claim, wherein the method comprises a) arranging a reactant into contact with the catalyst for performing the chemical reaction in a reactor to form the solid carbon product; b) performing the chemical reaction at a temperature of 550 - 1000 °C in the reactor; and c) recovering at least the solid carbon product.

18. The method according to claim 17, wherein the solid carbon product comprises an allotrope of carbon and / or graphitic structure, and the allotrope and / or graphitic structure comprises carbon nanofibers, carbon nanotubes, single wall carbon nanotubes, multiwalled carbon nanotubes, carbon nano onions, carbon nano shells, carbon micro shells, carbon coils, amorphous carbon, graphene, graphite fibers, graphite, or any combination thereof.

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