JP7365360B2 - Method for producing solid composites - Google Patents

Description

The present invention relates to a method for producing solid composites, especially mineral-containing composites.

Many industrial processes require large amounts of both energy and carbon. Examples of such processes include the production of steel from iron ore minerals, as well as the production of silicon from silica minerals. Fossil fuels such as coal are often the primary energy and carbon source. For example, metallurgical coke from the coking of high quality bituminous caking coal is the primary form of carbon used in the steel industry, particularly in the feedstock to blast furnaces. These industrial sectors are major emitters of greenhouse gases (particularly _CO2 ) and are actively seeking alternative low-emission means of supplying the energy and carbon needed in their processes.

While many renewable energy sources can be used to meet the energy demands of such industrial processes and reduce their _CO2 emissions, there are many renewable energy sources that can be used directly to meet the carbon demands of these industrial processes. Biomass is the only renewable energy source available.

Ore beneficiation is a process commonly used to improve the quality (purity) of raw minerals such as iron ore. It usually involves pulverization, thus producing fine minerals. This fine powder is then reduced to large particles, e.g. through pelletizing or briquetting, in order to make the fine powder into a feed in the form of large particles, such as pellets and briquettes, suitable for the intended process, e.g. as feed to a blast furnace. It is necessary to Clays such as bentonite are commonly used as binders. However, inorganic binders tend to introduce undesirable inorganic impurities into the process, which can have a negative impact on the main process and may ultimately leave the process as slag and waste. Is required. The organic binder can also form a complex with the mineral to be treated, in particular through physical and/or chemical interactions, becoming part of the carbon required for the process. Desirable if possible. Chemical reactions between binders and minerals are advantageous in producing composites with high mechanical strength.

The "carbon" required by the industrial sectors mentioned above is usually a reactant, e.g. a reducing agent to reduce iron ore to iron or to reduce silica to silicon, but carbon , can also be an energy source. As used herein, "carbon" does not necessarily mean pure carbon, but primarily refers to carbonaceous materials that are rich in carbon.

Metallurgical coke and charcoal are typical examples of these "carbon" materials. The close contact between the carbonaceous material and the mineral to be reacted (reduced) in the composite will have many beneficial effects in accelerating the process and increasing process efficiency.

In the process of manufacturing the carbon material and/or preparing the carbon material in such a way that the carbon material within the required particle size range can be fed to the intended industrial process, for example a blast furnace or an electric arc furnace. In the subsequent process, many fines may be generated. For example, a lot of metallurgical coke fines can be generated when metallurgical coke is crushed so that coke within the required particle size range can be produced and fed to a blast furnace. These fine coke powders cannot be fed directly to a blast furnace and have a lower market value than coke lumps. Another example is the generation of biochar fines during the production and preparation of biochar as a feedstock that can be fed to electric arc furnaces for silicon production. Again, biochar powder cannot be fed to an arc furnace and has a lower market value than biochar lumps. The production of bulk carbon materials using corresponding fine powders would be an important commercial achievement. In particular, lump carbon materials produced from fine powders should meet the quality requirements of the intended use, for example coke lumps should have sufficient mechanical strength as required in use in blast furnaces for producing steel. or the biochar mass should have sufficient mechanical strength as required for use in electric arc furnaces for producing silicon.

The scope of the invention should in no way be limited by the examples cited above. Other examples can be cited where fines should be large particles because large particles have a higher commercial value than fines.

From heat treatment of biomass at high temperatures, bio-crude can be produced and can be used as a binder or as a component in a binder. A typical type of biocrude is bio-oil from the pyrolysis of biomass, which also produces a solid by-product called biochar. Upon heating, the bio-oil can solidify with the removal of volatiles. Bio-oils are rich in reactive structures and functional groups that can react with minerals resulting in very strong bonds between minerals and biocrude-derived constituents. . Hydrothermal liquefaction of biomass can also produce reactive biocrude. The biocrude may also act as a binder for other materials such as metallurgical coke fines and/or biochar fines.

Organic binders can decompose at elevated temperatures releasing flammable volatiles. Using carbon as a reductant can also produce gases such as CO, which is a gas with a useful calorific value. Recovery of the energy value of these volatiles and gases is important to the energy efficiency of the overall process.

The carbon in the organic binder is part of the carbon needed in mineral reforming processes, such as in the case of reductants for reducing iron ore to iron in blast furnaces or similar processes. It can also be.

Therefore, developing organic binders from biomass and/or sending the carbon in close contact with the ore (or other materials to be combined) in the complex to a high temperature process, for example when reducing iron ore to iron. That is what is required.

According to a first aspect of the invention there is provided a method of manufacturing a solid composite, the method comprising:
To provide a biocrude formed from heat treatment of a carbonaceous feedstock containing biomass and capable of solidifying at high temperatures;
mixing the biocrude with a solid or paste to form a green composite; and heating the green composite to produce a solidified solid composite;
including.

Embodiments of the invention have significant advantages. In particular, the solid composites produced can have relatively high density and strength. Furthermore, the produced solid composite can have a relatively low sulfur content, and the biocrude cannot introduce undesirable impurities into the composite. Additionally, the biocrude may contain useful chemical species that can act as fluxing agents, for example in subsequent steelmaking processes.

The term "biomass" as used herein means any material obtained from living or recently living organisms. Although biomass is a preferred feedstock for organic binder production due to its potential carbon neutrality and other properties of biomass, other carbonaceous feedstocks may also be used as feedstocks. It includes a variety of carbon-containing renewable and non-renewable feedstocks, including, but not limited to, coal, solid waste, or mixtures thereof. Solid wastes may include, but are not limited to, agricultural wastes, forestry wastes, and domestic/municipal solid wastes, or residues from the processing of carbonaceous feedstocks. In fact, many solid wastes are considered bimass in the broadest sense. Alternatively, biomass is at least a significant component of many solid wastes.

The term "thermal treatment" as used herein is intended to include within its scope any process at elevated temperatures in the presence or absence of additional substances. For example, pyrolysis of biomass under an inert, oxidizing, or reducing atmosphere is a heat treatment process. Hydrothermal treatment of biomass in subcritical, critical, or supercritical water is another heat treatment process.

The term "biocrude" as used herein is intended to include any liquid or paste product from the thermal processing of biomass or other carbonaceous feedstocks. Bio-oil from the pyrolysis of biomass is a typical biocrude.

The term "biochar" (or "charcoal") as used herein is intended to include the solid product from the thermal processing of biomass or other carbonaceous feedstocks.
The term "composite" as used herein is intended to include within its scope any material that is composed of two or more component materials with different properties. "Green composite" means a mixture of precursors for producing the final solid composite. The green composites may be in the shape of pellets and spheres, or any other regular or irregular shape, and of any size.

The methods of the invention may be carried out over a wide range of relative ratios of biocrude to solid to produce solid composites with widely varying compositions and properties.
In one embodiment, the solid includes a mineral such as iron ore or silica. For example, the solid may be magnetite iron ore.

In another embodiment, the solid includes solid carbon material. For example, the solid may be metallurgical coke, biochar, or charcoal.
In one embodiment, the solid may have a wide range of particle sizes. For example, beneficent magnetite iron ore fines, alone or together with magnetite ore chunks, may be mixed with bio-oil to produce a green composite. The solid may contain impurities including, but not limited to, water.

In further embodiments, the solid may be in the form of a slurry containing water or other chemicals.
In embodiments, the solids include mixed solids. For example, the solid may be a mixture of magnetite iron ore and hematite iron ore together with other impurities. As another option, the solid may be a mixture of ore and biochar, or a mixture of ore and metallurgical coke.

In further embodiments, the green composite may include a fluxing agent, such as lime, to aid in subsequent processing of the composite.
In still further embodiments, the green composite may include additional chemicals, including catalysts, to accelerate solidification of the composite.

The step of heating the green composite may be carried out by heating the green composite to a temperature of 100-600°C, preferably 150-450°C, even more preferably 200-350°C. Heating may be performed under an inert, or reducing, or oxidizing atmosphere.

In another embodiment, heating the green composite may be performed by heating the green composite to a temperature above 600° C. under an inert, or reducing, or oxidizing atmosphere.

In embodiments, heating the green composite is performed in stages. For example, the temperature may be increased gradually at different heating rates and with varying hold times at selected temperature levels.

The method comprises carbonizing biocrude-derived carbonaceous components in the composite at elevated temperatures, preferably above 600°C, more preferably above 800°C, and even more, for the purpose of carbonizing biocrude-derived carbonaceous components in the composite, in particular but not limited to. A further step of carbonizing the composite may be included, preferably above 1000°C.

The method includes a further step of burning the composite through reaction with an oxidizing agent, for example air, in order to at least partially melt or recrystallize the solids in the composite to achieve better mechanical strength. may include.

According to a second aspect of the invention there is provided a method of manufacturing a solid composite, the method comprising:
To provide a biocrude formed from heat treatment of a carbonaceous feedstock containing biomass and capable of solidifying at high temperatures;
providing biochar formed from thermal treatment of carbonaceous feedstock containing biomass;
mixing the biocrude and biochar with a solid or paste to form a green composite; and heating the green composite to produce a solidified solid composite;
including.

By including biochar in the green composite, the carbon content of the composite can be advantageously increased. Biochar and biocrude may be produced from heat treatment of the same or different carbonaceous feedstocks.

According to a third aspect of the invention there is provided a method of manufacturing a solid composite, the method comprising:
To provide a biocrude formed from heat treatment of a carbonaceous feedstock containing biomass and capable of solidifying at high temperatures;
mixing the biocrude with a solid or paste to form a green composite;
heating the green composite to produce a solidified solid composite; and recovering volatile materials released from heating the green composite;
including.

According to a fourth aspect of the invention there is provided a method of manufacturing a solid composite, the method comprising:
To provide a biocrude formed from heat treatment of a carbonaceous feedstock containing biomass and capable of solidifying at high temperatures;
providing biochar formed from thermal treatment of carbonaceous feedstock containing biomass;
mixing biocrude and biochar with a solid or paste to form a green composite;
heating the green composite to produce a solidified solid composite; and recovering volatile materials released from heating the green composite;
including.

Biochar and biocrude may be produced from heat treatment of the same or different carbonaceous feedstocks.
In an embodiment of the third or fourth aspect of the invention, the step of recovering the volatile material comprises supplying the volatile material to a combustion device to provide thermal energy for heating the green composite. include.

In a further embodiment of the third or fourth aspect of the invention, recovering the volatile material comprises cooling the volatile material to form a liquid and non-condensable gas mixture. Liquids or non-condensable gas mixtures may be used individually or together as fuels to provide the thermal energy required for heating the green complex or for other purposes.

In specific embodiments of the third or fourth aspect of the invention, the recovered volatiles are used as fuel for power generation. For this purpose, any suitable power generation method known now or in the future may be used, for example the use of gas engines or gas turbines.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIG.

FIG. 1 is a flow diagram of a method of manufacturing a solid composite according to an embodiment of the invention.

Embodiments of the invention relate to methods of manufacturing solid composites. To produce a solid composite, a biocrude formed through heat treatment of biomass or other carbonaceous feedstock or mixtures thereof is provided, and the biocrude can be solidified by heating. Without necessarily subscribing to any particular theory, the solidification process involves the evaporation of water and light species from the biocrude, as well as reactive species and functional groups in the biocrude, resulting in green composites. It involves complex chemical reactions that also involve the solids that form part of the body. Although the description of embodiments herein focuses on bio-oil from the pyrolysis of biomass, the biocrude of the present invention is not limited to only bio-oil. A variety of biomass pyrolysis techniques now known or to be invented in the future may be used to produce bio-oil. For example, the crushing pyrolysis technique (PCT/AU2011/000741) works very well for the production of bio-oil for the production of composites using the method of the invention. Pyrolysis processes typically also produce a solid byproduct, biochar, and gaseous byproducts, including noncondensable gases. Biochar can also be used as a feedstock for the production of the solid composite of the present invention.

Although bio-oil is mostly liquid, those skilled in the art will recognize that bio-oil may contain colloids and even solids (including biochar). In addition to water, bio-oils can contain numerous organic compounds with a wide variety of chemical functionalities, especially oxygen-containing functional groups. Bio-oils may also contain dissolved minerals and solids, such as sodium, potassium, magnesium, and calcium salts. They may have beneficial effects in subsequent processes using the complex as feedstock. For example, they can act as fluxing agents in blast furnaces in the steel industry. In some pyrolysis processes, bio-oil is produced in the form of a paste or slurry. Bio-oil and biochar slurries are produced directly in several pyrolysis processes.

The bio-oil is mixed with solids to produce a green composite. In embodiments, bio-oil is mixed with magnetite iron ore to produce a green composite comprising bio-oil and magnetite. In another embodiment, bio-oil and biochar are mixed with magnetite ore to produce a green composite. In further embodiments, various additional chemical species are also added to the mixture to produce green composites with different properties.

In further embodiments, bio-oil is mixed with carbon materials to produce green composites. The carbon material can be metallurgical coke or biochar or any solid from heat treatment of carbonaceous feedstock. Additional chemicals, including catalysts, may also be components of the green composite.

The mixing process may be performed in various ways and the green composite may be manufactured in various shapes. The bio-oil and solids may be pressed into a green composite of the required shape. In embodiments, a disc pelletizer is used to mix and rotate bio-oil, which may also include biochar or any other component chemicals, and iron ore into a spherical shape. In a further embodiment, a drum pelletizer is used. The relative proportions of bio-oil, iron ore, and other components, including biochar and additional chemicals, in the complex are determined according to the needs of subsequent processing using the complex. It may vary over a wide range to suit the gender.

The green composite is then heated to produce the final solid composite article. Heating may be performed in a variety of ways to solidify the composite under an inert, reducing, or oxidizing atmosphere.
During the heating process, numerous physical processes and chemical reactions can occur. Moisture, for example in the bio-oil or in the iron ore, will evaporate. Some of the light components in the bio-oil will also evaporate. Depending on the temperature, the reactive functional groups in the bio-oil will also undergo various reactions, particularly cracking reactions and polymerization reactions, to produce additional lighter and heavier components. The heavy components are particularly important for binding solid (eg ore) particles together.

Without necessarily subscribing to any particular theory, the components in the bio-oil may also react with solids (e.g. iron ore, biochar, or other carbon materials) to form bio-oil components and iron ore. may form some new chemical bonds between This type of chemical bonding is much stronger than physical interactions/forces and contributes significantly to the mechanical strength of the composite article.

Heating the green composite may be done in a variety of ways. In embodiments, the green composite is heated under an oxidizing atmosphere to combust at least some of the bio-oil components. Combustion will heat the green composite to high temperatures causing some degree of melting/sintering of the iron ore, where recrystallization or other physico-chemical processes occur and lead to high mechanical A strong composite may result. Simultaneously with combustion, some iron ore may also be at least partially reduced. The combustion process may be performed on the green composite or on the final composite article.

Composites derived from bio-oil and iron ore and/or composites derived from bio-oil and metallurgical coke can be used as part of the feedstock to blast furnaces in the steel industry. A composite derived from bio-oil and solid biochar (or other types of charcoal) can be fed to an electric arc furnace for producing silicon.

The volatiles released from heating the green composite can contain a number of combustible components. If heating is performed at relatively low temperatures (eg, less than about 600° C.), some of these volatile components may be condensed to produce liquid fuels and non-condensable gaseous fuels.

Iron ore can be a very good catalyst for reforming released volatiles into light gases. Accordingly, in specific embodiments, the composite fabrication of the present invention is used to integrate with a power generation process, where the volatiles and gases released from the heating of the green composite are used for power generation. Examples of these power generation devices include, but are not limited to, gas engines, gas turbines, and fuel cells.

Referring now to FIG. 1, a flowchart is shown illustrating a method 100 according to a specific embodiment of the invention.
A first step 102 provides a biocrude that can be formed and solidified through heat treatment of biomass. In this particular embodiment, the biocrude is bio-oil obtained from pyrolysis of biomass.

At step 104, biochar is provided. Although bio-oil and biochar are generally produced simultaneously from the pyrolysis of the same biomass, bio-oil and biochar may be produced from different biomass and using different thermal treatment processes.

Specific examples of pyrolysis processes are described in further detail in PCT International Patent Application PCT/AU2011/000741.
In the next step 106, the bio-oil and biochar are mixed together with solids to form a green composite. In this particular embodiment, the solid is magnetite iron ore, particularly magnetite iron ore fines after beneficiation. Instead of biochar and iron ore, the solids may be biochar fines produced during the production and preparation of biochar in silicon manufacturing processes. In a further embodiment, silica may be added to form a green composite, such that the silica in the final composite article is in intimate contact with the carbon and the silica is reduced in an electric arc furnace. This promotes the formation of silicon. Mixing may occur at room temperature. In this particular example, mixing is performed to form the desired shape. The green composite may be formed through pressing.

The green composite is then heated in step 108 to a temperature at which the bio-oil undergoes complex physical and chemical processes to solidify. The bond between the C-containing component, including the reaction product from the bio-oil, and the magnetite ore includes physical forces and chemical bonds.

In step 110, volatiles released from reactions involving the bio-oil are recovered to extract their energy value. They can also be used as chemical feedstocks for other chemical processes.

In the following claims and in the above description of the invention, the word ``comprise'' is used in the following claims and in the above description of the invention, except where the context requires otherwise due to express language or required implication. , or variations such as "comprises" or "comprising" are used in an inclusive sense, i.e., specifying the presence of the recited feature, but not limiting the scope of the invention. This does not exclude the presence or provision of further features in various embodiments.

Claims (13)

1. A method of manufacturing a solid composite, comprising:
providing a bio-oil capable of solidifying at high temperatures formed from the pyrolysis of a carbonaceous feedstock comprising biomass;
mixing the bio-oil with a solid or paste to form a green composite; and heating the green composite to perform physical and chemical processes involving reactive species and functional groups in the bio-oil. producing a solidified solid composite subject to a process;
including;
here,
the solid or paste contains iron ore;
the solidified solid composite constitutes part of the feedstock to a blast furnace or electric arc furnace;
Method. 2. The method of claim 1, wherein the bio-oil comprises a flowable liquid or a non-flowable paste. 3. A method according to claim 1 or claim 2, wherein the solid or paste comprises a carbon material. 4. The method of claim 3, wherein the solid comprises metallurgical coke fines. 4. The method of claim 3, wherein the solid comprises biochar. 10. The method of claim 1, further comprising providing biochar formed from the thermal treatment of a carbonaceous feedstock comprising biomass, and mixing the biochar with the bio-oil and the solids to form a green composite. 6. The method according to any one of items 5 to 5. 7. A method according to any preceding claim, further comprising the step of recovering volatiles and other gases released from the heating of the green composite. 8. The method of claim 7, wherein the recovered volatiles and other gases are combusted to provide energy for heating the green composite. 8. The method of claim 7, wherein the recovered volatiles and other gases are used to generate electricity. 10. A method according to any one of claims 1 to 9, wherein the step of heating the green composite is performed in stages. 11. The method according to any one of claims 1 to 10, wherein the step of heating the green composite is performed to at least partially melt or sinter and/or carbonize the green composite. . A method according to any one of claims 1 to 11, wherein the step of heating the green composite is performed by heating the green composite to burn out organic constituents in the green composite. . 13. A method according to any preceding claim, further comprising the step of providing a catalyst to increase the rate of solidification of the green composite.

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