Method for providing raw material for an industrial process

Abstract

This invention discloses a method for providing raw materials for industrial processes, particularly for steel production. The method comprises the following steps: - baking a material comprising biomass in a reactor by thermochemically treating the material at a temperature between 200°C and 600°C to obtain biomass; - extracting the biomass from the reactor at a first temperature up to 600°C; - providing the bulk material at a second temperature between 0°C and 100°C; - mixing the biomass with the bulk material, thereby cooling the biomass through the bulk material, and obtaining a mixture of the bulk material and biomass at a third temperature below the auto-ignition temperature of the mixture; and - using the mixture to provide raw materials for industrial processes.

Description

[Technical Field]

[0001] This invention relates to a method for providing raw materials for industrial processes. [Previous Technology]

[0002] Currently, a major challenge in industry, particularly in the steel industry and power plants, is reducing CO2 emissions. One interesting possibility is the use of biomass. However, this has been found to be economically unfeasible because producing charcoal from biomass is extremely expensive compared to fossil fuels.

[0003] Therefore, the object of the present invention is to provide a method that allows for improved technical and economic feasibility of biomass production and utilization by integrating the method into another process, particularly the steelmaking process.

[0004] According to the WHO, carbon footprint is a measure of the impact of an activity (in this case, the production of steel and iron) on the amount of carbon dioxide (CO2) produced by burning fossil fuels, and is expressed as the weight of CO2 emissions produced in tons.

[0005] Using biomass in the steelmaking process is very difficult because biomass contains a large amount of volatiles. Therefore, directly applying biomass in the steelmaking process would be counterproductive.

[0006] a. When injected into a blast furnace, the conditions at the tuyeres will require a large amount of oxygen to maintain the desired temperature, typically >2000°C. This will necessitate the combustion of additional coal and / or coke. In addition to the negative economic impact, this also significantly reduces the CO2 emission reductions achievable through the use of biomass.

[0007] b. In the case of a sinter plant, the use of high-volatile solid fuels such as biomass in the sintering bed is also not recommended. In fact, from a safety perspective, high volatile content needs to be avoided because volatiles can accumulate in the exhaust gas and may cause fires in the gas purification facilities of the sinter plant.

[0008] c. In the case of a pellet plant, the use of high-volatile solid fuels in iron ore pelleting is also not recommended. High volatile content can lead to accumulation in exhaust gases and may cause fires in the gas purification facilities of the pellet plant.

[0009] d. In the case of electric arc furnaces, for example, when replacing petroleum coke (petroleum coke) in an electric arc furnace, the biomass also needs to have a very low volatile matter content. In this case, the goal is to foam the slag through carbon gasification. This requires a certain residence time, which cannot be achieved if the volatile matter content is high.

[0010] In addition, high-volatile solid fuels can reduce the product quality of sintering plants and pellet plants, thus negatively impacting plant productivity.

[0011] Therefore, before biomass can be used in the steelmaking process, it needs to be treated to reduce its volatile content. This is known in principle and has been practiced, whether in blast furnaces (BF) or as fuel in sintering plants and pellet plants.

[0012] However, this is usually still insufficient to make the use of biomass economically viable. [Summary of the Invention]

[0013] The object of the present invention is to provide a method for reducing the CO2 footprint of industrial processes while making the use of biomass economically feasible. This object is achieved by the method according to claim 1.

[0014] This invention provides a method for providing raw materials for industrial processes, particularly for steel production, the method comprising:

[0015] a. In a reactor, a biomass-containing baking material is baked by thermochemical treatment of the baking material at a temperature from 200°C to 600°C to obtain biomass coal.

[0016] b. Extract biomass from the reactor at a first temperature up to 600°C.

[0017] c. Provide bulk material at a second temperature between 0°C and 100°C.

[0018] d. Mixing bio-coal with bulk materials, thereby cooling the bio-coal through the bulk materials, and

[0019] A mixture of bulk material and biomass is obtained at a third temperature, which is below the auto-ignition temperature of the mixture, and

[0020] e. Using mixtures to provide raw materials for industrial processes.

[0021] Therefore, this method allows for rapid and efficient cooling of hot biomass (also known as roasted biomass, biochar, charcoal) and simultaneously allows it to be more useful in industrial production and power generation, especially in the steelmaking process.

[0022] In particular, the CO2 footprint of industrial production and power generation, especially steelmaking processes, is reduced due to the replacement of fossil fuels with biomass.

[0023] Preferably, bio-coal between 5% v / v and 95% v / v is mixed with bulk material between 95% v / v and 5% v / v. As with typical particulate and / or bulk materials, a volume of bio-coal or bulk material typically includes spaces or voids between the particles. For example, 1 m³ of bio-coal typically only contains bio-coal to a certain extent, while the spaces between the bio-coal particles are filled with gas, such as air. To determine the volume percentage of each component, a single component (bio-coal or bulk material) can be filled into a measuring container, where the surface level of the component corresponds to a certain volume. It will be understood that the volume of the mixture can be reduced due to the voids between the particles; for example, mixing 1 m³ of bio-coal with 1 m³ of bulk material may produce less than 2 m³ of mixture because some of the bulk material particles fill the voids between the bio-coal particles, and vice versa.

[0024] The term "bulk material" refers not only to a single material having homogeneous components, but also to a mixture or other combination of several bulk materials. Bulk material may be dry. Alternatively, bulk material may include residual moisture.

[0025] In an embodiment, a cooling fluid is added during the cooling step, which may be selected from water and an inert gas such as nitrogen.

[0026] In an embodiment, the method includes grinding and / or crushing the bio-coal before mixing it with bulk materials.

[0027] In one embodiment, the grinding and / or crushing of bio-coal and / or the mixing of bio-coal with bulk materials can be carried out under an inert atmosphere. This inert atmosphere can be obtained by reducing the oxygen content in the atmosphere, for example by adding nitrogen and steam and / or water, which will evaporate and generate steam when in contact with hot bio-coal.

[0028] Preferably, biomass is extracted from the reactor at a first temperature not exceeding 500°C, and more preferably between 200°C and 450°C.

[0029] Preferably, the bulk material has a second temperature not exceeding 50°C, and more preferably between 15°C and 35°C.

[0030] The method may also include grinding and / or crushing the mixture of bulk materials and biomass.

[0031] The products of this baking process can also be mixed with iron (Fe)-containing materials, and then advantageously integrated, for example, into sintering and / or pelletizing processes or added as fuel to EAFs (electric arc furnaces) and / or blast furnaces. Such iron (Fe)-containing materials can be selected from iron ores, iron oxides such as magnetite (Fe3O4) or hematite (Fe2O3), together with gangue minerals, waste or residual materials, sintering and / or pelletizing feed.

[0032] In an embodiment, the mixture of cooled bulk material and biomass can be mixed with other materials, such as other solid fuels (such as coke or coal), and is readily available for use in any industrial production and power generation.

[0033] An unexpected advantage of this method is that it provides a safer product that is easier to transport and store compared to 100% biomass processing. In fact, the mixture of the two materials is a safe product that will not spontaneously combust during transport and storage. The product does not require storage in an inert atmosphere, making it easier to handle and less costly.

[0034] Cooling biomass with a second bulk material stream and transporting and storing it as a mixture brings the advantage of not requiring inertization and always preventing spontaneous combustion.

[0035] Another advantage is that cooling hot biomass with a second bulk material stream will result in lower investment and operating costs compared to facilities with dedicated hot biomass cooling systems.

[0036] Classic roasted biomass tends to be easily reignited during storage and transportation, and therefore requires stronger precautions compared to mineral coal, such as nitrogen inertization. This is especially true at biomass production sites, during and after the cooling systems traditionally used in biomass production. The method described above, in which biomass is mixed with a second bulk material stream and transported and stored as a mixture, offers the advantage of not requiring inertization and always avoids spontaneous combustion.

[0037] Although bio-coal may reignite at specific points in the mixture, the flame cannot spread and cannot develop into an expanded fire or hazardous situation. This is due to the fact that the bulk materials are mixed in a proportion such that the second material can completely dissipate the heat from the reignited bio-coal in order to prevent a chain reaction throughout the material mixture. The mixing ratio may vary depending on the bulk materials used in the mixture, but the volume ratio of bio-coal to bulk materials is typically in the range of 5% to 95%.

[0038] Depending on the materials used, mixtures, unlike biomass coal itself, are not covered by the ATEX rules specified in Directive 2014 / 34 / EU. Therefore, the transport and handling of mixtures are much safer and cheaper than handling biomass coal alone.

[0039] The proposed method of mixing the produced bio-coal with other non-flammable materials is advantageous.

[0040] Compared with conventional roasting plants that produce biomass, the proposed method for cooling hot biomass eliminates the need for dedicated cooling equipment.

[0041] "Torrefying" or "torrefaction" refers to a process in which the starting material is subjected to some form of heat treatment. Torrefying is a form of thermochemical treatment (e.g., see https: / / en.wikipedia.org / wiki / Thermochemical) or pyrolysis of biomass. Although a temperature range between 200°C and 320°C is sometimes associated with the term "torrefying," a wider range is associated in the context of this invention. In this context, the temperature for the torrefying process can be from about 200°C to about 600°C, preferably at least 250°C, 275°C, 300°C, 325°C, 350°C, 375°C, or 400°C. The highest temperature is preferably below 600°C, 575°C, 550°C, 525°C, 500°C, 475°C, 450°C, 452°C, or below 400°C. Typically, torrefying is carried out at atmospheric pressure and under anaerobic (i.e., without air) conditions. During the roasting process, the water and excess volatiles contained in the biomass are released, and the biopolymers (cellulose, hemicellulose, and lignin) partially decompose, releasing various types of volatiles. The final product is the remaining solid, dry, blackened material, which is called roasted biomass or biomass. As will be clearly presented below, roasting can be performed not only on biomass but also on other organic materials.

[0042] During the roasting process, biomass (or roasting material) typically loses up to 80% of its mass (on the basis of being completely dry), while its volume remains largely unchanged. The gaseous energy (volatiles) can be used as heating fuel for the roasting process and secondary processes (such as hot water or power generation). After roasting, the roasting material can be densified using conventional densification equipment, typically forming clumps or pellets, to increase its mass and energy density and improve its hydrophobic properties. Unlike the raw biomass / roasting material, the final product may repel water and can therefore be stored in humid air or rain without significant changes in moisture content or calorific value.

[0043] The baking process is often referred to as “mild pyrolysis”, in which organic compounds are partially degraded and form combustible gases. However, in this document, pyrolysis and carbonization processes are also included under the term “baking”. More generally, in the context of this invention, baking may also be referred to as “pyrolysis” and baking materials may be referred to as “pyrolytic materials”.

[0044] If roasting materials including biomass are roasted, this produces what is called roasted biomass (biomass), which has many special properties. The first property is hydrophobicity; the material loses its natural properties of hygroscopicity and biodegradability, and is therefore more stable during storage than hydrophilic, unroasted biomass (such as wood and straw). In addition, burning roasted biomass produces less smoke compared to burning unroasted biomass.

[0045] In fact, the roasting of biomass produces a large amount of gas. Depending on the fixed carbon content of the initial product, typically 20% to 50% of the energy from the roasting material / biomass is recovered in gaseous / liquid form. A small portion of this energy is used in the roasting process, and the remainder can be used, for example, for drying the biomass.

[0046] When a high carbon fixation content is required, the relationship between gaseous products and solid products increases, resulting in excess gaseous energy due to the partial gasification of baking materials / biomass (volatiles). This excess gaseous energy can be readily used to reduce the consumption of other fossil fuels in industrial processes, and thus further reduce the carbon footprint of industrial processes. Steam is required in many industrial operations. Therefore, the gas can be used to produce steam in dedicated boilers. In addition, excess gaseous energy can be used in burner systems. In the case of iron or steel plants, it can be introduced into the ignition hood of sintering machines, or into the combustion chamber of pellet plants, for heating cowpers in coal GAD (grinding and drying) plants, and in rolling mills, etc.

[0047] The types of biomass used in this method include, but are not limited to, dedicated energy crops, agricultural crop residues, forestry residues, algae, wood processing residues, municipal waste, wet waste, crop waste, dedicated grass, woody energy crops, industrial waste, classified municipal solid waste (MSW), municipal timber waste, demolition timber, furniture waste and / or waste from furniture production.

[0048] The bulk material used in this method includes all kinds of granular or powdered materials suitable for reducing the combustion temperature of biomass coal. More specifically, the material may include at least one iron-containing material, such as iron ore, iron oxides such as magnetite (Fe3O4) or hematite (Fe2O3), typically together with gangue minerals and waste or residual materials, sintered and / or pellet feed. The iron-containing material includes at least 5 wt.% iron. Additionally or alternatively, the bulk material may include coal, petroleum coke, etc., sometimes together with waste or residual materials and / or additives. The bulk material may also include plastic materials. It should be understood that mixtures of any of the above materials may also be used.

[0049] In this method, preferably, biomass can be mixed with bulk materials of up to 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35% or 30% v / v.

[0050] In this method, preferably, biomass can be mixed with more than 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80% v / v of bulk material.

[0051] This method may also utilize non-biomass waste, such as plastics and / or rubber. In this method, the baking material may include at least 5% v / v of non-biomass material. In addition, it may include up to 5%, 7%, 10%, 12%, 15%, 17%, 20%, 23%, 25%, 30%, 35%, or 40% v / v of non-biomass material.

[0052] According to an embodiment, the baking material includes iron-containing byproducts derived from steel production, such as oily sludge and / or mill scrap. Preferably, these byproducts can therefore replace some of the biomass in the methods described above. Such byproducts can therefore be used in amounts of at least 5% v / v of the baking material and / or in amounts up to 5%, 7%, 10%, 12%, 15%, 17%, 20%, 23%, 25%, 30%, 35%, or 40% v / v. When such oily sludge and / or mill scrap are integrated into the baking process, the cost situation can be significantly improved. The oil from the oily mill scrap will decompose into a gaseous form and leave the baking process with the baking gases. Currently, some sintering plant operations are restricted in their use of byproducts due to limitations in gas purification systems. Integrating such byproducts into another process can offer the advantage of not requiring additional investment in sintering plant gas purification units to comply with legal restrictions.

[0053] In embodiments, waste heat from industrial operations, power plants, steel mills, etc., and / or industrial gases such as blast furnace gas are utilized during the baking process to maximize the production of volatiles and gases and to maximize the value of the products from the baking process. Incorporating the baking process into industrial operations allows for the supply of low-cost energy from other sources, such as waste heat from steel mills or power plants, and / or the utilization of other gases to maximize the value of the products from the pyrolysis process.

[0054] In addition to biomass coal, a gas phase is also generated. When this gas phase is cooled, a condensable liquid phase is produced. Since other energy sources are readily available "free" in steel mills or power plants, this liquid phase can be separated and used as a separate CO2 lean product in other industries to further reduce the CO2 footprint.

[0055] Mixing can be carried out in various ways, such as active mixing by mechanically mixing the bulk material and biomass pellets (and optional other components) in a suitable container. Suitable apparatus includes needle mixers, paddle mixers, or rotary mixers. Mixing can also be carried out more or less passively, for example by simultaneously dumping the bulk material pellets and biomass pellets onto a conveyor belt or into a container, which will also result in at least some degree of mixing. Other suitable mixing methods known in the art can also be used. Optionally, mixing can be combined with the loading of transport containers, such as trucks, shipping containers, train cars, ships, etc. This can be a form of passive mixing as noted above, or it can be combined with active mixing that takes place just before the pellet material is loaded into the transport container.

[0056] Preferably, the method further includes forming a composite from a mixture of bulk materials and biomass. In particular, each composite may be solid and may include granular iron-containing materials and biomass.

Implementation Method

[0058] As shown in Figure 1, the materials to be roasted are collected in raw material plant 1, such as forests or recycling centers, which are typically sources of waste to be pyrolyzed. In raw material plant 1, the components of the materials to be roasted, such as biomass, wood, forest residues, plastics, rubber, or any other type of by-product suitable for pyrolysis, are collected and stored; then, the materials are conveyed to crushing and sorting unit 3 via conveyor belt 2. In crushing and sorting unit 3, the particle size of the raw materials is reduced to a size range that allows for easy transport and further processing. The crushed and sorted raw materials now have a uniform size between 20 mm and 50 cm and are conveyed to drying unit 5 via conveyor belt 4. In unit 5, the moisture content of the raw materials is reduced to about 30% w / w or less. After drying, the materials are then transported to roasting unit 7 via conveyor belt 6, where they are roasted under anaerobic conditions at a temperature of about 200°C to 550°C.

[0059] The roasted raw materials are then discharged from the roasting unit 7 to the biomass discharge unit 9 via conveyor belt 8. From the biomass discharge unit 9, the hot biomass is transported on conveyor belt 10 to the crushing unit 15, and after crushing, it is transported via another conveyor belt 16 to the mixing unit 17. Such a mixing unit 17 is typically a mixing drum, a paddle mixing unit, etc.

[0060] Bulk materials such as iron ore, limestone, and dolomite are stored in silo 11 for use as cooling materials. When needed, the bulk materials are conveyed from silo 11 via conveyor belt 12 to bulk material conditioning unit 13, which is typically used for grinding, drying, etc., and then conveyed to mixing unit 17 via another conveyor belt 14. At mixing unit 17, it is mixed with hot bio-coal to form a cooled mixture of bio-coal and bulk materials.

[0061] Other materials for adjusting the mixing properties may be added to the mixing unit 17. These other materials may be solid or liquid and are used to adjust the properties of the mixture, but not for cooling purposes. One such material may be a binder, which makes it easier to form pellets from the mixture of biomass and bulk materials, and the pellets can be further processed more easily. This other material may be added to the mixing unit 17 via conveyor belt 18.

[0062] The mixture, including biomass and bulk materials and optional additional materials, is discharged from the mixing unit 17 to a silo via conveyor belt 19 or for further processing before use.

[0063] It should be noted that steps 3, 4, 5, 6, 12, 13 and 18 marked with an asterisk in Figure 1 are optional steps.

[0064] As an alternative to conveyor belts, other types of conveying equipment, such as screw conveyors, chain conveyors, or any other suitable type of conveyor, may be used in any of the above steps. For transporting materials over longer distances, trucks or ships may be used.

[0065] The entire process may occur in one location, or specific steps may occur in different locations.

[0066] In FIG2, the flowcharts of different operations of the preferred embodiment are represented by a series of different blocks describing the process steps.

[0067] At the top of the flowchart, below the box “Start”, in the first step, the raw materials for the process are provided. The raw materials used for roasting / pyrolysis (i.e. roasting materials) typically include forest residues as a mixture of deciduous and coniferous wood chips (peeled or unpeeled) and other fresh wood, other waste materials such as SFR (Solid Recovered Fuel) or others.

[0068] In the next step, “Drying the Raw Material,” the roasting / pyrolysis raw material may be dried to reduce the moisture content to as low as 5% w / w or less, and then the dried raw material is fed into the roasting / pyrolysis reactor. In the next step, “Roasting / Pyrolysis of the Raw Material – Charcoal,” the raw material is roasted in a temperature range from 200°C to 600°C. At the end of the roasting process, the roasted raw material (charcoal / biomass) is discharged into a cooling system. In this stage, the temperature of the roasted raw material is the same as the set roasting temperature (200–600°C).

[0069] As an alternative to completely cooling biomass / coke in a dedicated cooling system using water and air, a bulk material with a temperature of around 20°C is provided as a coolant.

[0070] Optionally, in order to improve mixing and cooling, water may be injected into the mixture, and indirect cooling supplied by cold air may be used in addition to the bulk materials.

[0071] In the step "Providing Bulk Material as Coolant", bulk material with a temperature of approximately 20°C is provided, and in the step "Mixing Components and Cooling Charcoal", it is mixed with hot biomass / charcoal having a temperature above 350°C at this stage. A mixing volume ratio between biomass / charcoal and the cold bulk material can be used, ranging from 1:19 to 19:1. This mixing ratio can be adjusted as needed. In one example, this may correspond to a mixing mass ratio of 1:9. The charcoal is cooled, and the bulk material is heated. Such a mixing operation produces a mixture with a temperature below 60°C. This process step can be carried out under inert conditions. The inert gas can be nitrogen or water vapor. In the case of injecting water into the mixing unit, this can also create inert conditions by generating water vapor.

[0072] Finally, in the final step “Storing the mixed and cooled charcoal (no inerting required)”, the mixed and cooled material is stored until further use.

[0073] Although the technical content of the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any modifications and refinements made by those skilled in the art without departing from the spirit of the present invention should be included within the scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims. [Simplified Explanation of the Diagram]

[0057] Figure 1 is a schematic diagram of different devices used in an embodiment of the present invention. Figure 2 is a flowchart of different operations according to an embodiment of the present invention.

Claims

1. A method for providing raw materials for an industrial process, particularly steel production, the method comprising: In a reactor, the biomass-containing baking material is baked by thermochemical treatment at a temperature of 200°C to 600°C to obtain biomass coal. The biomass coal is extracted from the reactor at a first temperature up to 600°C. Bulk material is provided at a second temperature between 0°C and 100°C. The biomass coal is mixed with the bulk material, thereby cooling the biomass coal through the bulk material. A mixture of the bulk material and the biomass coal is obtained at a third temperature below the auto-ignition temperature of the mixture, and the mixture is used to provide the raw material for the industrial process.

2. The method as described in claim 1, wherein the bio-coal between 5% v / v and 95% v / v is mixed with the bulk material between 95% v / v and 5% v / v.

3. The bulk material includes residual moisture as described in claim 1 or 2 above.

4. As described in claim 1 or 2 above, a cooling fluid is added in the cooling step, the cooling fluid being selected from water and an inert gas, such as nitrogen.

5. The method as described in claim 1 or 2 above, wherein the method includes grinding and / or crushing the bio-coal before mixing it with the bulk material.

6. The method as described in claim 1 or 2 above, wherein the grinding and / or crushing of the bio-coal and / or the mixing of the bio-coal with the bulk material are carried out under an inert atmosphere.

7. The method as described in claim 1 or 2 above, wherein the bio-coal is extracted from the reactor at a first temperature not exceeding 500°C, and preferably between 200°C and 450°C.

8. The method as described in claim 1 or 2 above, wherein the bulk material has a second temperature not exceeding 50°C, and preferably between 15°C and 35°C.

9. The method as described in claim 1 or 2 above, wherein the method comprises grinding and / or crushing the mixture of the bulk material and the biomass.

10. The biomass described in claim 1 or 2 above includes dedicated energy crops, agricultural crop residues, forestry residues, algae, wood processing residues, municipal waste, wet waste, crop waste, dedicated grass, woody energy crops, industrial waste, classified municipal solid waste (MSW), municipal timber waste, demolished timber, furniture waste and / or waste from furniture production.

11. The method as described in claim 1 or 2 above, wherein the bulk material comprises at least one iron-containing material, such as iron ore, iron oxides such as magnetite (Fe3O4) or hematite (Fe2O3), the iron-containing material generally together with gangue minerals and also together with waste or residual materials, sinter and / or pellet feed, the iron-containing material comprising at least 5 wt.% iron.

12. The method as described in claim 1 or 2 above, wherein the bulk material comprises at least one granular material, such as coal or petroleum coke, which is sometimes accompanied by waste or residual materials and / or additives.

13. The method as described in claim 1 or 2 above, wherein the baking material comprises at least 5% v / v of non-biomass waste, such as plastics and / or rubber.

14. The method as described in claim 1 or 2 above, wherein the baking material comprises at least 5% v / v of iron-containing byproducts derived from steel production, such as oily sludge and / or oily mill scrap.

15. The method as described in claim 1 or 2 above, further comprising forming a composite from the mixture of the bulk material and the biomass.

16. The method of claim 15, wherein each of the composites is a solid and comprises particulate iron-containing material and biomass.

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