A process for enriching gases generated in industrial processes, through the capture of the carbon dioxide contained within, and generating valuable products.

Description

1 / 10 “PROCESS FOR ENRICHING GASES GENERATED IN INDUSTRIAL PROCESSES, THROUGH THE CAPTURE OF THE CONTAINED CARBON DIOXIDE, AND GENERATING VALUE-ADDED PRODUCTS” Field of application (001) The present invention relates to the capture of gases generated in industrial processes, rich in combustible gases, for subsequent use in energy cogeneration. In addition to combustible gases, these also contain other inert gases, such as Carbon Dioxide and Nitrogen. Through collection and purification, using compounds that absorb CO2, a richer final gas with higher calorific value is obtained. The reacted material, formed by various carbonates, depending on the carbon dioxide absorbent reagent used, including examples of Ca and Mg carbonates, has various applications. State of the art (002) During industrial processes, chemical reactions occur. Among them, combustion. The combustion reaction is commonly characterized by the reaction of carbon with oxygen, generating CO and CO2. C + 1 / 2 O2 ^ CO C + O2 ^ CO2 (003) The production of CO is due to the incomplete combustion of carbon. In the blast furnace, this reaction is preferable because, by forming Carbon Monoxide (CO), it acts as a reducing agent for iron ore, that is, it has the capacity to remove the oxygen that constitutes the components of the ore, especially Fe2O3, transforming it into pure Fe. However, the large amount of carbon inside the blast furnace causes this element to mix with pure iron, forming pig iron. In the steelworks, the oxidation of the carbon contained in the pig iron occurs to produce steel. In this process, pure oxygen is blown in for the almost complete combustion of all the carbon contained in the molten metal, generating CO and CO2 gases. Petition 870260049316, dated 05 / 24 / 2026, page 4 / 20 2 / 10 (004) The generated gases mixed with very fine particulates called smoke are collected in industrial systems and treated along their path to accumulators called gasometers, or expelled, after cleaning, through chimneys. The treatment of the fumes consists of separating particulates through cyclones and precipitators; the gas is then washed, obtaining a sludge rich in iron. The clean gases are then stored in gasometers for use as fuel in other steelmaking processes. (005) The gases from industrial processes, originating from the coke oven, blast furnace, and steelworks, have different compositions due to the characteristics of the process, as shown in the following table: Table 1 - Analysis of typical gases in a steel mill Compound (%) Coke Oven Blast Furnace Steelmaking CO 7 28 60 CO2 2 12 18 H2 56 5 1 CH4 28 - 0 N2 4 55 18 Calorific Value (kcal / m3) 4200 800 1800 (006) These gases have considerable energy potential and are therefore economical; that is, they combust, releasing thermal energy for use as cogeneration. This allows plants to reduce energy costs due to reduced purchases of natural gas or LPG, for example, since these gases can supply stages of the steelmaking process, including: heating pig iron and steel ladles, heating boilers, reheating furnaces, and horizontal and vertical burners. Some plants have integrated thermoelectric plants that, through the combustion of these gases, generate electricity for the plant, making it self-sufficient. (007) The problem of not fully utilizing these gases is due to some technical characteristics. Among them, the low calorific value of blast furnace gas (800kcal / m3) and steelmaking gas (1800kcal / m3) stands out. Because of this, some plants prefer to discard these gases, requiring a combustion stage, Petition 870260049316, dated 05 / 24 / 2026, page 5 / 20 3 / 10 to convert all the carbon monoxide CO (toxic) into carbon dioxide, CO2, further increasing the generation of greenhouse gases, without any energy recovery from this reaction. (008) The current steelmaking process is one of the largest generators of greenhouse gases, accounting for 8% of the gases generated worldwide, alongside cement plants and thermal power plants. According to projections from the Global Carbon Budget, total CO2 emissions (including fossil fuels and changes in land use) are expected to reach 41.6 billion tons in 2024. The steel industry is responsible for approximately 7% to 9% of global CO2 emissions, according to the World Steel Association. In terms of tonnage, it is estimated that the steel industry contributes approximately 3 to 3.7 billion tons of CO2 annually, including direct and indirect emissions. The World Steel Association's Sustainability Indicators 2024 report indicates a global average of 1.92 tons of CO2 per ton of crude steel in 2023. (009) Another problem with storing the gases generated in the steelmaking process is their acidic nature. Carbon dioxide, CO2, and hydrogen sulfide, H2S, reduce the pH, being corrosive to pipelines and storage tanks, resulting in maintenance costs. (0010)The storage issue is also compromised, as part of the captured gas is rich in carbon dioxide, CO2 (inert), which reduces the energy storage capacity per volume, requiring investments in larger gasometers. (0011)Finding ways to capture these “dirty” gases and subject them to purification treatment will guarantee a financial return for companies, in addition to reducing their carbon footprint and reducing environmental liabilities. (0012) US patent 5536300 uses activated carbon-based absorbent compounds for the selective absorption of hydrocarbons such as methane, CH4, within a mixture of combustible gases. Using a natural gas purification process, the methane present (fuel) is absorbed by the activated carbon, and the nitrogen is not absorbed, being eliminated from the system. Subsequently, depressurization is performed, releasing the methane and achieving purities on the order of 98%. Petition 870260049316, dated 05 / 24 / 2026, page 6 / 20 4 / 10 (0013) Patent US7964020 proposes the use of selective membranes which allow the separation of gases, enabling the removal of carbon dioxide. This process does not directly store carbon dioxide, CO2. There is a need to use other permanent storage techniques, or to use the CO2 for other applications. (0014) The natural gas enrichment process, methane, also uses the technique of capturing CO2 via amine reagent, which forms stable compounds with CO2 and H2S, allowing CH4 to pass into storage, increasing its final content. Then, the reverse process occurs, which requires energy, so that CO2 and H2S are released, thus recycling the amine. (0015) Some authors suggest the use of steelmaking slag as a compound for CO2 capture. Patents CN117865536 and CN103111186 discuss the use of steelmaking slag. The slag is rich in CaO and MgO, forming calcium and magnesium hydroxides, Ca(OH)2 and Mg(OH)2, in contact with water. These hydroxides react with CO2, forming stable calcium and magnesium carbonates, CaCO3 and MgCO3. Since slag is a considerable environmental liability, it becomes strategic to reuse it as a carbonation agent. The carbonates formed, being stable, can be used in cement plants to reduce cement production costs. These compounds can also be reused within the steelmaking process itself, which consumes calcium carbonate as a generator of calcium oxide, used as a slag-forming agent in the production of pig iron and steel, which would lead to a reduction in the consumption of virgin calcium carbonate.The problem with these academic works is operationalizing and scaling up the data. What time frame, particle size, concentration, temperature, etc.? This issue was well explored in the article: “Carbon Dioxide Sequestration on Steel Slag, by Mo Liwu, 2018”. In this and other articles, studies are promoted using a pure gas as a CO2 source, conditioned in laboratory cylinders and not through sources resulting directly from industrial combustion. Petition 870260049316, dated 05 / 24 / 2026, page 7 / 20 5 / 10 Objectives of the invention (0016) In order to increase the energy efficiency of industrial gases, the present invention has developed a procedure for subjecting these "dirty" gases to a carbonation process via compounds rich in calcium and magnesium, Ca and Mg, such as steelmaking slag (blast furnace and steelworks), dust removal dust, steelmaking sludge, calcination residues (pre-lime), ash from combustion furnaces (calcination, thermoelectric, brickyards and charcoal kilns), mining residues, as well as minerals or mining residues of Serpentinite (Mg,Fe)3(Si2O5)(OH)4, Calcitic and Dolomitic Limestones CaCO3, MgCO3, Basalt, Dunite (Mg,Fe)2SiO4, and / or any other material with CO2 sequestration potential and alkaline nature, forming stable compounds for various applications. (0017) According to current processes, no technology has been found that uses mineral compounds with chemical affinity for CO2 to enrich steelmaking gases as a way to increase calorific value, reducing the carbon footprint and still generating stable products for civil construction or other use in a circular economy. (0018) As a way to reduce CO2 emissions from steel mills, reducing an environmental liability that is steelmaking slag and increasing the calorific value of steelmaking gases, the present invention was developed, whose proposal consists of using minerals, compounds and / or carbonatable phases within a reactor, into which the flow of steelmaking gases (coke oven, blast furnace and steelmaking) are injected. Inside the reactor, under controlled conditions, the carbonatable compounds and / or phases would form stable compounds with CO2, and the unreacted gases, rich in carbon monoxide, hydrogen and methane, would have their calorific value increased through the selective removal of carbon dioxide, and would pass directly through, being stored in gasometers for later use as fuel. (0019) The invention may be better understood through the following description, in accordance with the attached figures, where the FIG 1 represents the slag pretreatment. Petition 870260049316, dated 05 / 24 / 2026, page 8 / 20 6 / 10 FIG 2 represents the process of capturing and enriching industrial gases. FIG 3 represents the process of separating selective oxides from slag. FIG 4 represents the reactor used for controlled carbonation tests. (0020) As shown in FIG 1, the slag (1), or other suitably chosen carbonation agent, will be ground in the mill (2), or any other means of particle size reduction, obtaining a product with finer particle size (3), in order to increase its reactivity. The ground slag (3) will go to a tank (4) to form a pumpable pulp. In this tank, circulating water (5) and additives (6) will be added to reduce the surface tension of the water and / or adjust mixture parameters, helping in the reactivity with the injected CO2. Then the ready pulp will be pumped (7) to the carbonation reactor (13), shown in FIG 2. (0021) During the steelmaking process in the converter or electric arc furnace (8), the generated gases rich in CO and CO2 will be captured (9) and conducted to a gas treatment station in order to eliminate particulates. (0022) The idea of ​​this patent proposal is that the captured gases (9) will be enriched by capturing CO2 via carbonation of the slag and / or products contained in the pulp. By capturing the contained CO2, the aim is to increase the CO concentration, thus increasing the final calorific value of the treated gas, obtaining a richer gas, avoiding expenses with natural gas during use in other equipment and / or processes of the plant that have thermal needs that can be met by the enriched gas. (0023) For this purpose, the gases will be conducted to a collection tank (10), through a feed with a directional valve (11). The gas entering this system will circulate through the compressor (12) to a carbonation reactor (13), which contains a pulp rich in reactive material with CO2 (3), fed at “B”. Upon passing through this reactor, some of the CO2 is captured by the carbonation reaction. What did not react, due to residence time, returns Petition 870260049316, dated 05 / 24 / 2026, page 9 / 20 7 / 10 to the collector (10), which will be injected back into the reactor (13). This cyclic process ends when the maximum carbonation value is reached, via gas analysis. (0024) When the maximum enrichment value is reached, the gases will be conducted to the Gasometer (17), which becomes a rich fuel for use in the other processes. (0025) After saturation of the slag with CO2, forming stable carbonates, the pulp will be pumped (15) to filter presses (16) forming a cake rich in stable carbonates (18). (0026) In order to take advantage of the other elements present in the slag, the pulp (18) that comes out of the reactor (13) can be pumped (15) to a magnetic separator (19), and after separation, results in two types of materials, being the one rich in iron (20) and the one rich in carbonates (21), as shown in FIG 3. (0027) This separation may also be by gravimetry, since the iron-rich oxides (20) have a higher density compared to the carbonates (21) which are light. This separation may also be carried out by hydrocyclones, or by any other processes that allow the economic use of the fractions generated. Example 1 - Slag Carbonation Test with Steelmaking Gas (0028) In order to evaluate the potential of the invention, a controlled test was carried out using a mixture of gases prepared in the laboratory with a composition close to that of a steelmaking gas: Table 2 - Original gas composition for capture test Component Content (%) CO 60 CO2 20 N2 20 (0029) For this, a reactor made of stainless steel (FIG 4) was used, with a check valve, pressure gauge and safety valve. The reactor has temperature control, and can reach up to 120°C. (0030) Steelmaking slag was separated, with the following typical composition: Petition 870260049316, dated 05 / 24 / 2026, page 10 / 20 8 / 10 Table 3 - Composition of the steelmaking slag used in the experiments Compound Content (%) CaO 40.64 FeO 32.40 MnO 5.85 MgO 5.36 SiO2 11.55 (0031) The slag (1) was properly ground (2), then the pulp was made with water (B). Then it was placed in the reactor. Then the temperature was adjusted, reaching 50°C. When the temperature stabilized, the prepared gas mixture was injected to simulate the gas from the steel mill. When the pressure reached 4 bar, the reactions were allowed to proceed. (0032) After 30 minutes, a drop in pressure from 4 bar to 3.2 bar is observed. The drop of 0.8 bar means that CO2 was captured, reducing the partial pressure of the gas in the steelworks. (0033) The gas was collected before and after the test and analyzed, obtaining the following results: Table 4 - Analysis of gases before and after treatment Component Before (%) After (%) CO 60 75 CO2 20 0 N2 20 25 Calorific Value (kcal / m3) 1811 2264 (0034) According to the results, the laboratory test showed the proposal to be effective, which, using BOF slag residue, made it possible to enrich the steelmaking gas by 25% in its calorific value. (0035) According to the World Steel Association (Wordsteel.org), and several technical articles and publications from the steel industry, the composition of oxygen-fired steelmaking gas, or converter gas, is rich in carbon monoxide and can Petition 870260049316, dated 05 / 24 / 2026, page 11 / 20 9 / 10 vary considerably (Carbon Monoxide (CO): 55% to 70%; Carbon Dioxide (CO2): 10% to 20%; Nitrogen (N2): 10% to 20%; Hydrogen (H2): 1% to 5%; Water Vapor (H2O): 5% to 15%, with the latter content varying significantly depending on the gas treatment). An estimate of the average converter gas generation, according to the World Steel Association, would be 70 to 100 m3 (cubic meters) of gas per ton of crude steel. Considering an average volume of 85 m3 generated per ton of steel produced, containing an average of 15% carbon dioxide, the present patent application would have the capacity to reduce an average of up to 12.75 m3 of carbon dioxide per ton of steel produced, or the equivalent of 25.245 kg per ton of steel produced.Furthermore, it would have the capacity to increase, on average, the calorific value of the resulting gas by up to 33% after carbon dioxide sequestration, resulting in cleaner energy for the process, since this energy increase could be deducted from the consumption of natural gas or liquefied petroleum gas, which are necessary inputs for the steel production process. (0036) General technical estimates indicate that BOF slag generation is between 100 kg and 150 kg per ton of crude steel produced. As published by the World Steel Association, steel production in steel mills integrated with BOF converters represents approximately 71.1% (2023 data). This means approximately 1.345 billion tons of crude steel produced via the BOF route, resulting in approximately 135.5 to 201.8 million tons of BOF slag. According to technical literature, the chemical composition of BOF slag can vary considerably depending on the process, ranging from 34% to 55% CaO, 14% to 32% Fe2O3 / FeO, 8% to 20% SiO2, 1% to 10% MgO, 1% to 7% Al2O3, and in smaller proportions, may include manganese oxide (MnO), phosphorus oxide (P2O5), sulfate (S), and traces of other elements.Considering CaO and MgO as scavenging agents and the average content ranges of these oxides in the slag, the CO2 capture potential would be approximately 18 to 34.4 kg per ton of steel produced. Therefore, the average amount of slag produced per ton of steel would be sufficient to capture the average amount of CO2 generated in the BOF gas, leading to the total potential for gas purification. Petition 870260049316, dated 05 / 24 / 2026, page 12 / 20 10 / 10 generated and the optimization of its calorific value. In other words, the present invention will eliminate 100% of the CO2 produced by the BOF route steelmaking process. This means reducing CO2 emissions by approximately up to 1.67% per ton of total crude steel produced by the BOF process. Petition 870260049316, dated 05 / 24 / 2026, page 13 / 20

Claims

1 / 3 CLAIMS 1. “PROCESS FOR ENRICHING GASES GENERATED IN INDUSTRIAL PROCESSES, THROUGH THE CAPTURE OF THE CONTAINED CARBON DIOXIDE, AND WITH THE GENERATION OF VALUE PRODUCTS”, characterized by the treatment of gases through the selective capture of carbon dioxide CO2, through carbonation reagents, in various reactors that allow intimate contact between the gases to be enriched and the carbon dioxide CO2 capture reagents.

2. “PROCESS FOR ENRICHING GASES GENERATED IN INDUSTRIAL PROCESSES, THROUGH THE CAPTURE OF THE CONTAINED CARBON DIOXIDE, AND WITH THE GENERATION OF VALUE PRODUCTS”, according to claim 1, characterized by the use of co-products from industrial processes, such as steelmaking slag (blast furnace and steelworks), dust removal dust, steelmaking sludge, calcination residues (pre-lime), ash from combustion furnaces (calcination, thermoelectric, brickyards and charcoal production), mining residues, as well as minerals or mining residues of Serpentinite - (Mg,Fe)3(Si2Os)(OH)4, Calcitic and Dolomitic Limestones CaCO3, MgCO3, Basalt, Dunite (Mg,Fe)2SiO4, and / or any other reagent or material with potential CO2 sequestrants and alkaline in nature, acting as carbonation agents and consequently capturing carbon dioxide (CO2).

3. “PROCESS FOR ENRICHING GASES GENERATED IN INDUSTRIAL PROCESSES, THROUGH THE CAPTURE OF THE CONTAINED CARBON DIOXIDE, AND WITH THE GENERATION OF VALUE PRODUCTS”, according to claims 1 and 2, characterized by the capture of the same in tanks (temporary gasometers), where they will be subjected to a cyclic process of carbon dioxide capture, through reaction with a pulp containing carbonatable reagents described in claim 2.

4. “PROCESS FOR ENRICHING GASES GENERATED IN INDUSTRIAL PROCESSES, THROUGH THE CAPTURE OF THE CONTAINED CARBON DIOXIDE, AND WITH THE GENERATION OF VALUE PRODUCTS”, according to claims 1 and 3, characterized by the capture of carbon dioxide CO2, through the reaction of the gas and the reagents described in Petition 870250053108, dated 06 / 25 / 2025, page 1. 10 / 22 2 / 3 claim 2, in suitable reactors, which may be of the fluidized bed reactor, fixed bed reactor, bubbling reactor, moving bed reactor, slurry reactor, column reactor, upjet reactor, or any other types and models of reactors used for the present purpose described in this patent, and which may have controls for pressure, temperature, residence time, flow rate, pH and any other variables that may be used to optimize the yield of the reactions described in claims 1 and 2.

5. “PROCESS FOR ENRICHING GASES GENERATED IN INDUSTRIAL PROCESSES, THROUGH THE CAPTURE OF THE CONTAINED CARBON DIOXIDE, AND WITH THE GENERATION OF VALUE PRODUCTS”, according to claims 1 and 4, characterized by the generation of a final reacted pulp, containing carbonates, capable of being separated into parts rich in iron and other heavy metals, and in carbonates, and which, after proper separation by various suitable processes, can be recycled within the steelmaking process itself, or destined for other processes in which they will be properly reused.

6. “PROCESS FOR ENRICHING GASES GENERATED IN INDUSTRIAL PROCESSES, THROUGH THE CAPTURE OF THE CONTAINED CARBON DIOXIDE, AND WITH THE GENERATION OF VALUE PRODUCTS”, according to claims 1 and 5, characterized by the generation of a final reacted pulp, containing carbonates, which provide a reduction in CO2 emissions in the steelmaking process.

7. “PROCESS FOR ENRICHING GASES GENERATED IN INDUSTRIAL PROCESSES, THROUGH THE CAPTURE OF THE CONTAINED CARBON DIOXIDE, AND WITH THE GENERATION OF VALUE PRODUCTS”, according to claims 1 and 3, characterized by the use and recycling of industrial co-products, such as slag from steel mills (blast furnace and steelmaking), dust removal dust, steelmaking sludge, calcination residues (pre-lime), ash from combustion furnaces (calcination, thermoelectric, brickyards and charcoal production), mining residues, or other residues susceptible to carbonation and that can be used as CO2 sequestering agents, reducing the Petition 870250053108, dated 06 / 25 / 2025, page 1. 11 / 22 3 / 3 accumulation of environmental liabilities due to the various industrial processes that generate them.

8. “PROCESS FOR ENRICHING GASES GENERATED IN INDUSTRIAL PROCESSES, THROUGH THE CAPTURE OF CONTAINED CARBON DIOXIDE, AND WITH THE GENERATION OF VALUE-ADDED PRODUCTS”, according to claims 1 and 3, characterized by the treatment of gases through the selective capture of carbon dioxide (CO2), and which, after capture and enrichment of calorific value, will promote an increase in energy to be deducted from the consumption of natural gas, liquefied petroleum gas, or other additional energy source, necessary for the steel production process. Petition 870250053108, dated 06 / 25 / 2025, pp. 12 / 22

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