A method and device for blowing full-oxygen-co2-biomass baking in a ladle

Abstract

This invention discloses a method and apparatus for ladle combustion with oxygen-CO2-biomass. The method includes the following steps: the main combustion gas injection flow rate is gradually increased from 50%-70% of the designed maximum flow rate to 100%; when the oxygen volume fraction in the combustion zone decreases to 0.5%-1.5%, biomass is injected into the combustion zone at a preset initial amount using CO2 as the carrier gas, and the oxygen volume fraction in the oxygen-enriched gas is 80%-100%; after the ladle lining temperature reaches 600℃-750℃, the main combustion gas temperature is reduced... The gas injection flow rate is increased to 40%-70% of the design maximum flow rate, and the biomass injection rate is increased to 70%-100% of the maximum value, so that the heat of biomass combustion accounts for 20%-60% of the total heat supply in the combustion zone, and radiative heat transfer is enhanced. When the ladle lining temperature approaches the target baking temperature of 1000℃-1100℃, the main gas injection flow rate is gradually increased to 70%-100% of the design maximum flow rate, while the biomass injection rate is reduced to 0-60% of the maximum value, and the CO2 carrier gas injection flow rate is reduced simultaneously. The technical solution of this invention aims to balance combustion stability, radiative heat transfer efficiency, and energy conservation and emission reduction requirements.

Description

Technical Field

[0001] This invention relates to the field of metallurgical heating technology, and in particular to a method and apparatus for baking steel ladles with full oxygen-CO2-biomass injection. Background Technology

[0002] As a crucial piece of equipment in the steel smelting process for carrying and transferring molten steel, the temperature and thermal state of the steel lining have a significant impact on steel quality, smelting energy consumption, and production rhythm. Before being put into use or after repair, the steel ladle usually needs to be baked to remove moisture from the lining, increase the lining temperature, and establish a stable thermal state.

[0003] The ladle baking methods in related technologies mainly use natural gas, coke oven gas, or liquid fuels as combustion media, with air or oxygen-enriched air as the combustion-supporting gas. This results in the combustion temperature being significantly affected by nitrogen dilution, leading to problems such as low radiative heat transfer efficiency and long baking cycles, and is also detrimental to energy conservation and emission reduction.

[0004] Therefore, how to provide a ladle baking method that can take into account combustion stability, radiative heat transfer efficiency, and energy conservation and emission reduction requirements has become an urgent problem to be solved in the industry. Summary of the Invention

[0005] The main objective of this invention is to propose a method and apparatus for ladle-injected oxygen-CO2-biomass baking, which aims to balance combustion stability, radiative heat transfer efficiency, and energy conservation and emission reduction requirements.

[0006] To achieve the above objectives, this invention proposes a ladle-injection method for full oxygen-CO2-biomass baking. This method involves injecting main combustion gas, full oxygen or oxygen-enriched gas, and biomass transported by CO2 carrier gas into the combustion zone inside the ladle. The method is dynamically controlled in stages based on the ladle lining temperature and the oxygen volume fraction in the combustion zone, and includes the following steps: Step S1, Heating Stage: The main gas injection flow rate is gradually increased from 50%-70% of the design maximum flow rate to 100%. When the oxygen volume fraction in the combustion zone decreases to 0.5%-1.5%, CO2 is used as the carrier gas to inject biomass into the combustion zone at a preset initial amount, and the oxygen volume fraction in the oxygen-enriched gas is 80%-100%. Step S2, Enhanced Baking Stage: After the temperature of the ladle lining reaches 600℃-750℃, reduce the main gas injection flow rate to 40%-70% of the design maximum flow rate, increase the biomass injection rate to 70%-100% of the maximum value, so that the heat of biomass combustion accounts for 20%-60% of the total heat supply in the combustion zone, and enhance radiative heat transfer by increasing the proportion of biomass injection to form a carbon particle suspension flame with high radiation intensity. Step S3, Temperature Isostatic Stage: When the temperature of the ladle lining is close to the target baking temperature of 1000℃-1100℃, gradually increase the main gas injection flow rate to 70%-100% of the design maximum flow rate, while reducing the biomass injection rate to 0-60% of the maximum value, and simultaneously reduce the CO2 carrier gas injection flow rate to achieve uniform and stable temperature of the ladle lining.

[0007] In some embodiments, CO2 serves as both the carrier gas for biomass and the thermal conditioning medium in the combustion zone, for: forming a stable two-phase flow with biomass during injection to achieve stable delivery; and regulating the peak flame temperature and enhancing radiative heat transfer in the combustion zone through interaction with the all-oxygen combustion flame.

[0008] In some embodiments, the duration of the enhanced baking stage is 20%-40% of the total baking cycle, and the peak flame temperature is controlled to not exceed 1600°C during this stage by adjusting the CO2 carrier gas injection flow rate.

[0009] In some embodiments, biomass is injected into the ladle combustion zone in the form of solid carbon powder and forms a stable two-phase flow injection medium under the action of CO2 carrier gas. The powder-to-gas ratio of the two-phase flow is 0.05-0.25 kg / Nm³.

[0010] In some embodiments, phased dynamic control is achieved through the following heating ratio control, where the biomass heating ratio η is defined as: ; Among them, m∙ bio H represents the mass flow rate of biomass injected per unit time. bio For the lower heating value of biomass, η burn Q represents the combustion efficiency of biomass in the ladle combustion zone. fuel The heat provided by the combustion of the main gas; During the heating phase, η is controlled at 5%-15%; during the enhanced baking phase, η is controlled at 20%-60%; and during the temperature equalization phase, η is controlled at 0%-30%.

[0011] In some embodiments, the CO2 carrier gas injection flow rate is adjusted in conjunction with changes in the biomass injection rate to maintain a constant powder-to-gas ratio in the two-phase flow or to vary along a preset curve. The adjustment follows the formula below: ; Among them, V∙ co2 V∙ is the CO2 carrier gas injection flow rate, k is the powder-to-gas ratio coefficient, and V∙ base Based on the basic traffic.

[0012] In some embodiments, during the initial stage of heating, the main gas injection flow rate is controlled at 50%-60% of the design maximum flow rate, the oxygen injection flow rate is controlled at 60%-80% of the design maximum flow rate, the CO2 carrier gas injection flow rate is controlled at 30%-50% of the design maximum flow rate, and the biomass injection channel is kept closed to establish a low oxygen concentration environment and prevent the lining from heating up rapidly.

[0013] In some embodiments, the method is applicable to the baking of newly built steel ladles, minor repair steel ladles, or major repair steel ladles, wherein: the total baking cycle for newly built steel ladles is 72h-108h, with the enhanced baking stage accounting for 25%-35%; the total baking cycle for minor repair steel ladles is 36h-48h, with the enhanced baking stage accounting for 20%-30%; and the total baking cycle for major repair steel ladles is 72h-96h, with the enhanced baking stage accounting for 25%-40%.

[0014] The present invention also provides a ladle-blown oxygen-CO2-biomass baking apparatus for implementing the method provided in any of the foregoing embodiments, the apparatus comprising: Steel ladle baking oven body; The composite injection combustion device is installed on the ladle baking furnace body and is used to inject the main combustion gas, oxygen and two-phase injection medium formed by biomass and CO2 carrier gas into the combustion zone inside the ladle. The gas supply system, biomass supply system, oxygen supply system and CO2 supply system are respectively connected to the corresponding inlets of the combined injection combustion device; The detection system is used to detect the temperature inside the ladle and the composition of gases in the combustion zone; The control system is connected to the detection system and each supply system to perform phased closed-loop regulation of the flow rate of each injection medium based on the temperature and gas composition signals fed back by the detection.

[0015] In some embodiments, the composite injection combustion device adopts one of the coaxial, layered, or annular injection structures, and is located at the center of the ladle cover, with its nozzle axis aligned with the center line of the ladle.

[0016] The technical solution of this invention creates a safe combustion environment with low oxygen concentration by setting "the oxygen volume fraction in the combustion zone drops to 0.5%-1.5%" as the trigger condition for biomass injection, effectively avoiding premature and violent combustion or flameout of biomass in the high-temperature oxidation zone. This achieves stable and controllable injection of biomass under full oxygen conditions, solving the problem of difficulty in coordinating the two processes. Secondly, through three-stage flow ratio control, the main combustion gas is gradually increased to 100% and a stable flame is established during the heating stage; the biomass heating ratio is increased to 20%-60% and a high-radiation carbon particle suspended flame is formed during the enhanced baking stage; and the main combustion gas is adjusted back and the biomass flow rate is reduced during the isotherm stage. This achieves precise dynamic matching between heat supply and the thermal state of the ladle lining, ensuring baking efficiency while avoiding local overheating. At the same time, CO2 carrier gas participates in the control of each stage throughout the process. During the injection stage, it forms a stable two-phase flow with biomass to ensure transportation. During the combustion stage, its high heat capacity characteristics regulate the flame temperature and enhance radiative heat transfer, fully utilizing the dual functions of CO2 as a carrier gas for transportation and thermal regulation. This method significantly improves the baking thermal efficiency and reduces fossil energy consumption while ensuring the safe heating of the ladle lining, thus achieving low-energy consumption and low-carbon operation of the ladle baking process. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a flowchart of a ladle-injected oxygen-CO2-biomass baking method according to an embodiment of the present invention; Figure 2 This is a graph showing the changes in the injection flow rate and temperature of fuel gas, oxygen, biomass, CO2 carrier gas, and ladle lining in a ladle-blowing oxygen-CO2-biomass baking method provided in an embodiment of the present invention.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] In the iron and steel metallurgy industry, the ladle, as a key piece of equipment for carrying and transferring molten steel, directly affects the temperature stability of the molten steel and the energy consumption of smelting due to the quality of its lining baking. Traditional ladle baking uses air-assisted combustion, which suffers from problems such as low combustion efficiency, large flue gas volume, and slow temperature rise. With the development of oxy-fuel combustion technology, although the combustion temperature can be increased, excessively high flame temperatures can easily lead to localized overheating damage to the lining. At the same time, biomass, as a renewable low-carbon fuel, has poor injection stability and is difficult to coordinate with oxy-fuel combustion systems, limiting its application in ladle baking.

[0024] In existing ladle baking methods, there is a lack of effective synergy between oxy-fuel combustion and biomass injection. Oxy-fuel combustion flame temperatures can reach over 2000℃, far exceeding the safe operating temperature of refractory materials; while direct injection of biomass into the high-temperature oxidation zone easily leads to combustion runaway or flameout. Furthermore, CO2 is mostly passively present as exhaust gas or dilution gas, failing to fully utilize its dual functions of carrier gas transport and thermal regulation. Therefore, how to achieve an organic combination of oxy-fuel combustion, biomass, and CO2 carrier gas to improve baking thermal efficiency and reduce carbon emissions while ensuring the safe heating of the ladle lining has become a pressing problem for the industry.

[0025] Based on this, the inventors designed a method and apparatus for ladle baking with full oxygen-CO2-biomass injection. By dynamically adjusting the injection parameters of the main combustion gas, biomass and CO2 carrier gas in stages, the three are coordinated to significantly improve the thermal efficiency of ladle baking and reduce fossil energy consumption.

[0026] This invention proposes a method for baking a steel ladle using a combination of oxygen, CO2, and biomass. The method includes injecting main combustion gas, oxygen-enriched gas, and biomass transported by CO2 carrier gas into the combustion zone inside the steel ladle. The method is dynamically controlled in stages according to the temperature of the steel ladle lining and the oxygen volume fraction in the combustion zone, specifically including a heating stage, an enhanced baking stage, and a temperature equalization stage.

[0027] This application further proposes a method for ladle injection of full oxygen-CO2-biomass baking, in which main combustion gas, full oxygen or oxygen-enriched gas, and biomass transported by CO2 carrier gas are injected into the combustion zone inside the ladle, and the temperature of the ladle lining and the oxygen volume fraction in the combustion zone are dynamically controlled in stages.

[0028] The main fuel gas refers to the gas used as the base fuel, which can be natural gas, coke oven gas or converter gas, to provide basic heat and a stable combustion flame for the baking process.

[0029] Full oxygen or oxygen-enriched gas refers to combustion-supporting gas with an oxygen volume fraction of ≥80%. Specifically, cryogenic air separation oxygen generation equipment can be used to provide full oxygen with a purity of ≥99.5%, or pressure swing adsorption oxygen generation equipment can be used to provide oxygen-enriched gas with an oxygen concentration of 80%-99%. Compared with air-assisted combustion, it can significantly increase the combustion temperature and reduce the amount of flue gas.

[0030] Biomass transported by CO2 carrier gas refers to the use of carbon dioxide gas as a carrier to inject biomass pellets into the combustion zone. Specifically, the high density of CO2 can be used to form a stable two-phase flow, thereby achieving stable transport of biomass. At the same time, CO2 participates in combustion regulation as a thermal conditioning medium.

[0031] The ladle lining temperature is a key parameter reflecting the heated state of the ladle. Specifically, it can be detected in real time by multiple thermocouples arranged on the side walls and bottom of the ladle, providing a temperature triggering basis for phased conversion.

[0032] The oxygen volume fraction in the combustion zone is a key parameter reflecting the combustion state and safety. Specifically, it can be detected in real time by a zirconia oxygen analyzer installed in the combustion zone, providing a basis for gas composition for biomass injection start-up and combustion control.

[0033] Phased dynamic control refers to adjusting the injection flow rates of main combustion gas, biomass, oxygen, and CO2 according to a preset program based on changes in thermal demand throughout the baking process. Specifically, this can be automatically executed by the control system based on feedback signals from temperature and gas composition, forming and matching a preset ladle baking curve to achieve efficient, uniform, and safe heating of the ladle lining.

[0034] Specifically, during the entire ladle baking process, the composite injection combustion device is located at the center of the ladle cover, featuring independent gas injection channels, oxygen injection channels, and a mixed injection channel for biomass and CO2 carrier gas. These three media are injected sequentially into the combustion zone inside the ladle through their respective channels. The control system collects temperature signals from multi-point thermocouples and oxygen concentration signals from a zirconia oxygen analyzer in real time, comparing them with a preset ladle baking curve. Based on the deviation, it automatically adjusts the injection flow rate of each media, achieving phased dynamic control. The main gas serves as the basic heat source throughout the process, with its flow rate adjusted within the design maximum range of 50%-100%. Oxygen is continuously supplied in a full-oxygen or oxygen-enriched form, maintaining an oxygen concentration of 80%-100%. Biomass injection begins after the oxygen concentration drops to 0.5%-1.5%, with its flow rate adjusted within the design maximum range of 0-100%. CO2 is injected in conjunction with biomass as the carrier gas, and its flow rate is independently adjusted according to the combustion state to control flame temperature and radiation characteristics. Through the coordinated injection and dynamic control of these media, optimized control of the entire ladle baking process is achieved.

[0035] Please refer to the following: Figure 1 and Figure 2 In the embodiments provided in this application, the method of ladle injection of all-oxygen-CO2-biomass baking includes the following steps: Step S0, Ladle Baking Preparation Stage: Place the ladle to be baked in the ladle baking station. Start the ladle baking system when the ladle is in a non-smelting, non-molten steel state. Use a composite injection device to inject main combustion gas and supply oxygen to the combustion zone inside the ladle to establish a stable combustion flame.

[0036] Among them, "ladles awaiting baking" refers to ladles that need to be brought into a thermal state or have moisture removed, specifically including three types: newly built ladles, ladles undergoing minor repairs, and ladles undergoing major repairs. "Non-smelting, molten steel-free state" refers to a safe state where the ladle is completely isolated from smelting production and contains no liquid metal. This can be achieved by confirming that the connection between the ladle and the smelting equipment is completely disconnected, and that the temperature inside the ladle is below 100°C with no liquid metal residue. "Establishing a stable combustion flame" refers to forming a continuous, uniform, and non-extinguishing combustion state, which can be achieved by controlling the ignition sequence, adjusting the air-fuel ratio, and monitoring flame stability.

[0037] Specifically, in this step, the ladle to be baked is first hoisted to the baking station, confirming that the ladle is disconnected from the smelting equipment, there is no molten steel residue inside, and the temperature is below 100°C. The ladle baking system is then started, and the composite injection combustion device begins to inject main combustion gas and oxygen to establish a stable combustion flame. Using natural gas as the gas source, the initial main combustion gas flow rate is lower than the starting value in step S1, and the oxygen flow rate is moderate, forming a stable ignition and preheating combustion zone, laying the foundation for the formal heating in subsequent steps.

[0038] Step S1, Initial heating stage of baking: The main gas injection flow rate is gradually increased from 50%-70% of the maximum design flow rate to 100%. When the oxygen volume fraction in the combustion zone decreases to 0.5%-1.5%, CO2 is used as the carrier gas to inject biomass into the combustion zone at a preset initial amount, and the oxygen volume fraction in the oxygen-enriched gas is 80%-100%.

[0039] The gradual increase from 50%-70% to 100% refers to using a lower initial flow rate during the startup phase to ensure safe ignition, followed by increasing the flow rate to full load operation at a set rate. This can be achieved using a linear ramp function or a segmented step, and is automatically executed by the preset timing program of the control system.

[0040] The oxygen volume fraction of 0.5%-1.5% refers to the key threshold range for triggering biomass injection, which can be detected in real time by a zirconia oxygen analyzer. This low-oxygen environment can prevent premature and violent combustion of biomass.

[0041] The preset initial amount refers to the initial feed amount when biomass injection is started. Specifically, it can be set to 20%-50% of the design maximum flow rate, which ensures stable ignition while avoiding excessive initial load.

[0042] Specifically, in this step, after the control system executes the startup procedure, the main gas flow rate gradually increases from 50%-70% of the maximum design flow rate to 100%, while the oxygen flow rate simultaneously increases to 80%-100% of the design flow rate. The oxygen volume fraction in the combustion zone is monitored in real time. When it drops to the 0.5%-1.5% range, the biomass feeder is automatically turned on to its initial frequency and the CO2 carrier gas valve to its initial opening, injecting biomass into the combustion zone at a preset initial amount. During this stage, the temperature rises from ambient temperature to 600℃-750℃.

[0043] Step S2, Mid-term Intensive Baking Stage: After the ladle lining temperature reaches 600℃-750℃, reduce the main gas injection flow rate to 40%-70% of the design maximum flow rate, increase the biomass injection rate to 70%-100% of the maximum value, so that the heat of biomass combustion accounts for 20%-60% of the total heat supply in the combustion zone, and achieve stable transport and uniform dispersion of biomass in the combustion zone by adjusting the CO2 carrier gas injection rate.

[0044] The 600℃-750℃ range refers to the temperature trigger range for the transition from step S1 to step S2, which can be determined by detecting the lining temperature using multi-point thermocouples. The biomass combustion heat accounting for 20%-60% refers to adjusting the injection ratio of biomass to main fuel gas to achieve the target range for biomass heating. This can be achieved by the control system monitoring the flow rates of the two fuels in real time and adjusting the ratio accordingly. Stable delivery and uniform dispersion mean that the biomass particles do not clog or deposit in the pipeline and are evenly distributed after being injected into the combustion zone. This can be achieved by maintaining a suitable powder-to-gas ratio and optimizing the injector structure.

[0045] When the lining temperature reaches the trigger range, the control system reduces the main gas flow rate to 40%-70% and increases the biomass injection rate to 70%-100%, adjusting the ratio to ensure that biomass heating accounts for 20%-60%. Simultaneously, the CO2 carrier gas injection rate is adjusted to ensure stable biomass delivery and uniform dispersion, forming a high-radiation carbon particle flame. During this stage, the temperature rises from 650℃ to 950℃-1050℃.

[0046] Step S3, Later Temperature Adjustment Stage: When the temperature of the ladle lining approaches the target baking temperature, gradually increase the main gas injection flow rate to 70%-100% of the design maximum flow rate, while reducing the biomass injection rate to 0-60% of the maximum value, and simultaneously reduce the CO2 carrier gas injection flow rate to achieve uniform temperature adjustment of the ladle lining.

[0047] Approaching the target baking temperature means that the lining temperature reaches 90%-95% of the target value, which can be determined by multi-point thermocouple detection. Uniform adjustment means reducing the temperature difference between different parts of the ladle lining, which can be achieved by adjusting the flow rate of each medium to make the flame temperature field more uniform and extending the temperature uniformity time.

[0048] When the lining temperature is detected to be close to the target value, the control system increases the main combustion gas flow rate to 70%-100%, reduces the biomass injection rate to 0-60%, and simultaneously reduces the CO2 carrier gas flow rate. At this time, the flame characteristics change, and the radiative and convective heat transfer ratios are readjusted, promoting temperature homogenization of the ladle lining. The temperature difference at each point is monitored, and if the temperature difference is small, the system prepares to proceed to step S4. In this stage, the temperature rises to and stabilizes at the target temperature.

[0049] Step S4, Baking Completion Stage: Gradually reduce the biomass injection rate and CO2 carrier gas injection rate to make the main gas supply the primary heat source. Based on the temperature changes of the ladle lining, maintain or gradually reduce the main gas injection flow rate to achieve stable and uniform ladle lining temperature and complete the ladle baking process.

[0050] Gradual reduction refers to reducing biomass and CO2 at a set rate until they are completely shut off, avoiding combustion fluctuations caused by sudden cutoff. This can be achieved using a linear ramp or segmented step method. Maintaining or gradually reducing refers to selecting a heat preservation or slow cooling strategy based on subsequent production needs. This can be automatically executed by the control system according to scheduling instructions.

[0051] Once the lining temperature reaches and stabilizes at the target temperature, the control system reduces the biomass injection rate and CO2 carrier gas flow rate to 0 or the minimum value at a set rate. The main gas supply, depending on scheduling requirements, either maintains the current proportion of heat preservation or gradually decreases at a set rate to achieve slow cooling. Temperature changes are monitored to ensure stability, ultimately completing the baking process.

[0052] Compared with existing technologies, traditional ladle baking uses air-assisted combustion, resulting in low combustion efficiency and large flue gas volume; or it uses a single oxy-fuel combustion method, leading to excessively high flame temperature and large thermal shock to the lining; and the direct injection of biomass into the high-temperature oxidation zone is prone to combustion runaway, lacking systematic coordinated control. This solution, however, injects three media—main combustion gas, oxy-fuel or oxygen-enriched gas, and biomass transported by CO2 carrier gas—into the combustion zone in a coordinated manner. Through dual-parameter feedback of ladle lining temperature and oxygen volume fraction in the combustion zone, and through dynamic control in five stages (S0-S4), it achieves organic synergy among oxy-fuel combustion, biomass, and CO2 carrier gas, solving the problem of refined control throughout the baking process. This significantly improves baking thermal efficiency, reduces fossil fuel consumption and carbon emissions, and protects the ladle lining from thermal shock damage, achieving efficient, low-carbon, and safe operation of ladle baking.

[0053] In some embodiments, CO2 serves as both the carrier gas for biomass and the thermal conditioning medium in the combustion zone, for: forming a stable two-phase flow with biomass during injection to achieve stable delivery; and regulating the peak flame temperature and enhancing radiative heat transfer in the combustion zone through interaction with the all-oxygen combustion flame.

[0054] In these embodiments of the present application, CO2 has a dual function during the ladle baking process, namely, it serves as both the carrier gas for biomass and the thermal conditioning medium for the combustion zone.

[0055] When CO2 is used as the carrier gas, the key is to form a stable gas-solid two-phase flow. Compared with conventional nitrogen or air carrier gases, CO2 has a higher density, which gives it a stronger particle suspension capacity and kinetic energy carrying capacity. When biomass carbon powder enters the conveying pipeline from the silo, CO2 forms a negative pressure at the throat of the injector at a certain flow rate, drawing in and entraining carbon powder particles to form a uniformly mixed two-phase flow.

[0056] The high density of CO2 allows toner particles to remain in a better suspended state within the pipeline, reducing the risk of sedimentation and blockage caused by gravity settling. Simultaneously, the chemical inertness of CO2 prevents premature oxidation or spontaneous combustion of the toner during transport, improving system safety. By controlling the toner-to-gas ratio within a suitable range and dynamically adjusting it according to the needs of different stages, stable transport across all operating conditions—from startup to full load and then to load reduction—can be achieved.

[0057] After CO2 enters the combustion zone as a thermal conditioning medium, it interacts with the high-temperature flame generated by oxy-fuel combustion, thus performing a thermal conditioning function. The flame temperature of oxy-fuel combustion is extremely high, easily exceeding the safe service temperature of refractory materials. The introduction of CO2 achieves cooling regulation through two mechanisms: physical endothermic reaction and chemical dissociation. On the one hand, it absorbs heat using its high heat capacity; on the other hand, it undergoes an endothermic dissociation reaction at high temperatures, thereby controlling the peak flame temperature within a safe range.

[0058] Meanwhile, CO2 significantly enhances radiative heat transfer. As a triatomic gas, CO2 exhibits strong absorption and emission capabilities in specific infrared bands. The increased CO2 concentration in high-temperature flue gas directly increases its radiative capacity. During the biomass carbon powder combustion stage, the solid radiation from the carbon powder particles and the gaseous radiation from CO2 create a superposition effect, significantly improving the flame's radiative heat transfer efficiency.

[0059] Throughout the roasting process, the two functions of CO2 are dynamically adjusted and coordinated. In the initial stage, the carrier gas function is the primary function, ensuring the safe start-up and stable delivery of biomass. In the enhanced stage, both functions are emphasized, ensuring high-flow delivery while constructing a high-radiation flame through concentration control. In the later stage, the functions are gradually weakened to coordinate with the adjustment of the energy structure. The control system optimizes the CO2 flow distribution in real time based on feedback from temperature and gas composition, achieving decoupling and coordination between carrier gas delivery and thermal regulation.

[0060] Compared with related technologies, traditional methods have a single function for CO2, with biomass transport and flame temperature control operating independently, lacking an effective synergistic mechanism. This solution, through an innovative dual-function design of CO2, simultaneously solves the technical challenges of stable biomass transport and all-oxygen combustion temperature control, achieving overall optimization of resource utilization and thermal performance.

[0061] In some embodiments, the duration of the enhanced baking stage is 20%-40% of the total baking cycle, and the peak flame temperature is controlled to not exceed 1600°C during this stage by adjusting the CO2 carrier gas injection flow rate.

[0062] The extended baking stage lasts 20%-40% of the total baking cycle, with the key being the scientific definition of this stage's time proportion. 20% is the lower limit, ensuring sufficient time to build up the ladle's heat capacity; 40% is the upper limit, preventing excessive extension that could lead to overheating of the lining. This proportion varies depending on the ladle type: typically 25%-35% for newly built ladles, 20%-30% for minor repairs, and 25%-40% for major repairs.

[0063] The core of controlling the peak flame temperature to below 1600℃ by adjusting the CO2 carrier gas injection flow rate lies in an independent temperature control mechanism. 1600℃ is the safe upper limit, based on the safe operating temperature setting of the refractory materials. When the flame temperature approaches this upper limit, the CO2 carrier gas flow rate is increased to utilize its endothermic effect for cooling; when the temperature is within the safe range, the CO2 flow rate is reduced to optimize energy efficiency. This adjustment is independent of the flow rate regulation of the main combustion gas and biomass, achieving decoupling between temperature control and stable heating.

[0064] Throughout the baking process, the control system monitors the flame temperature in real time and dynamically adjusts the CO2 carrier gas flow rate to ensure that the temperature during the enhanced baking stage does not exceed the safe upper limit of 1600℃, while the duration of this stage is strictly controlled within 20%-40% of the total cycle. Compared with related technologies, traditional methods lack quantitative definition of the duration of the enhanced stage and rely on single temperature control methods. This solution achieves safe and efficient operation of the enhanced stage through quantitative setting of time proportion and independent temperature control of the CO2 carrier gas.

[0065] In some embodiments, biomass is injected into the ladle combustion zone in the form of solid carbon powder and forms a stable two-phase flow injection medium under the action of CO2 carrier gas. The powder-to-gas ratio of the two-phase flow is 0.05-0.25 kg / Nm³.

[0066] The core of solid biomass carbon powder lies in its pre-treated fuel form, which has better flowability and energy density.

[0067] The powder-to-gas ratio is 0.05-0.25 kg / Nm³, with the core focus on the quantitative control of the two-phase flow dilute phase transport. 0.05 kg / Nm³ is the lower limit, above the critical deposition concentration to prevent particle deposition and clogging; 0.25 kg / Nm³ is the upper limit, below the critical clogging concentration to prevent pipeline blockage. Within this range, carbon powder particles maintain a stable suspended state in the CO2 carrier gas, achieving uniform dispersion and stable transport. Different values ​​within this range are used for different stages: 0.05-0.10 kg / Nm³ for the start-up stage, 0.15-0.25 kg / Nm³ for the enhancement stage, and 0.05-0.15 kg / Nm³ for the later stages.

[0068] Throughout the baking process, the control system dynamically adjusts the powder-to-gas ratio within the range of 0.05-0.25 kg / Nm³ according to the stage requirements, ensuring stable two-phase flow delivery under all operating conditions. Compared with related technologies, traditional methods lack precise control over the powder-to-gas ratio, often resulting in sedimentation or blockage. This solution achieves stable delivery and uniform dispersion of biomass through quantitative control within the range of 0.05-0.25 kg / Nm³.

[0069] In some embodiments, phased dynamic control is achieved through the following heating ratio control, where the biomass heating ratio η is defined as: ; Among them, m∙ bio H represents the mass flow rate of biomass injected per unit time. bio For the lower heating value of biomass, η burn Q represents the combustion efficiency of biomass in the ladle combustion zone. fuel The heat provided by the combustion of the main gas; During the heating phase, η is controlled at 5%-15%; during the enhanced baking phase, η is controlled at 20%-60%; and during the temperature equalization phase, η is controlled at 0%-30%.

[0070] In the above formula, the numerator represents the effective heat released by biomass combustion, while the denominator is the total heat. The ratio η between the two directly characterizes the energy structure.

[0071] During the heating phase, η is controlled at 5%-15%, with the core principle being that the main combustion gas plays a dominant role, while biomass serves only as an auxiliary start-up, ensuring stable combustion. During the enhanced baking phase, η is controlled at 20%-60%, with the core principle being to significantly increase the proportion of biomass, leveraging its high radiant properties to achieve efficient heating. During the temperature equalization phase, η is controlled at 0%-30%, with the core principle being to adjust the biomass proportion back to restore the dominant role of the main combustion gas and optimize combustion stability.

[0072] Throughout the baking process, the control system collects m∙ bio and Q fuel Combined with the preset H bio and η burn The actual η value is calculated and compared with the target range for each stage. The flow rates of each medium are automatically adjusted to bring η back to the target range, achieving precise quantitative control in stages. Compared with related technologies, traditional methods lack quantitative indicators and rely on experience-based judgment. This solution achieves the transformation from experience-based control to quantitative control through a mathematical model of η and three-stage range control.

[0073] In some embodiments, the CO2 carrier gas injection flow rate is adjusted in conjunction with changes in the biomass injection rate to maintain a constant powder-to-gas ratio in the two-phase flow or to vary along a preset curve. The adjustment follows the formula below: ; Among them, V∙ co2 V∙ is the CO2 carrier gas injection flow rate, k is the powder-to-gas ratio coefficient, and V∙ base Based on the basic traffic.

[0074] A linear model for coordinated regulation refers to establishing a mathematical relationship between CO2 flow rate and biomass mass. In the model, k is the powder-to-gas ratio coefficient, reflecting the required carrier gas volume per unit mass of biomass, and is set according to particle characteristics and conveying distance; V∙ base It serves as the base flow rate to ensure minimum transport energy and prevent sedimentation under low load conditions.

[0075] In these embodiments of this application, maintaining a constant powder-to-air ratio hinges on a fixed value for k and V∙ co2 With m∙ bio Proportional to ensure stable two-phase flow concentration; varies along a preset curve, the core lies in the k value or V∙ base The process is adjusted according to stages, so that the powder-to-air ratio changes according to a specific pattern to meet the needs of different stages.

[0076] Throughout the baking process, the control system selects parameter sets according to the stage program and calculates V∙ in real time. co2 A set value drives the CO2 flow valve to adjust, achieving coordinated operation with biomass and maintaining a constant or curve-dependent powder-to-gas ratio. Compared to related technologies, traditional methods involve fixed or independently adjusted CO2 flow rates, resulting in large fluctuations in the powder-to-gas ratio. This solution, through a linear linkage model, ensures stable delivery across the entire operating range.

[0077] In some embodiments, during the initial stage of heating, the main gas injection flow rate is controlled at 50%-60% of the design maximum flow rate, the oxygen injection flow rate is controlled at 60%-80% of the design maximum flow rate, the CO2 carrier gas injection flow rate is controlled at 30%-50% of the design maximum flow rate, and the biomass injection channel is kept closed to establish a low oxygen concentration environment and prevent the lining from heating up rapidly.

[0078] The main combustion gas content is 50%-60%, primarily for low-to-medium load startup in the initial stage, ensuring safe ignition and stable combustion, lower than the 70%-100% content in the later stages of step S1. Oxygen content is 60%-80%, primarily for a fuel-rich atmosphere below stoichiometric ratio, creating a weakly oxidizing environment in conjunction with the main combustion gas. CO2 content is 30%-50%, primarily for appropriate inert dilution, further suppressing flame intensity. The biomass channel is closed, primarily for absolute containment of the low-temperature zone, preventing incomplete combustion from producing carbon deposits or the accumulation of combustible gas.

[0079] The combination of these four elements forms a parameter combination of "rich fuel + partial oxygen + CO2 dilution + no biomass", resulting in a flame temperature that is significantly lower than the normal level of full oxygen combustion, with gentle heat transfer, ensuring safe dehydration of the lining.

[0080] Throughout the baking process, this parameter combination continues until the lining temperature reaches a safe threshold and the oxygen concentration drops to the biomass start-up range of 0.5%-1.5%. At this point, the control system automatically unlocks and switches to the normal injection program.

[0081] Compared to related technologies, traditional methods often use fixed parameters or inject biomass too early, which can easily lead to lining cracking or safety hazards. This solution achieves safe and controllable operation during the initial heating phase through specific parameter combinations and a locking mechanism.

[0082] In some embodiments, the method is applicable to the baking of newly built steel ladles, minor repair steel ladles, or major repair steel ladles, wherein: the total baking cycle for newly built steel ladles is 72h-108h, with the enhanced baking stage accounting for 25%-35%; the total baking cycle for minor repair steel ladles is 36h-48h, with the enhanced baking stage accounting for 20%-30%; and the total baking cycle for major repair steel ladles is 72h-96h, with the enhanced baking stage accounting for 25%-40%.

[0083] The preset intermediate temperature range is 600℃-700℃ or 650℃-750℃. The core lies in the temperature trigger determination during the transition from step S1 to S2. 600℃-700℃ is suitable for newly constructed steel ladles, ensuring sufficient dehydration; 650℃-750℃ is suitable for steel ladles undergoing minor or major repairs, accommodating faster temperature rise. The control system uses multi-point thermocouple detection, and automatically triggers the stage transition when the average or lowest value reaches this range.

[0084] The target baking temperature is 1000℃-1100℃, with the key being the final temperature target. 1000℃-1050℃ is suitable for minor repairs of steel ladles to avoid over-baking; 1050℃-1100℃ is suitable for newly built or major repairs of steel ladles to ensure sufficient heat capacity is established.

[0085] Throughout the baking process, these two temperature ranges constitute key transition points and the final target. The control system continuously compares the measured temperature and automatically performs transitions and adjustments to ensure that the target temperature is reached.

[0086] Compared to related technologies, traditional methods often use a uniform temperature and do not consider type differences. This solution achieves precise matching between stage transitions and ladle conditions by setting differentiated temperature ranges.

[0087] The present invention also provides a ladle-blown oxygen-CO2-biomass baking apparatus for implementing the method provided in any of the foregoing embodiments, the apparatus comprising: Steel ladle baking oven body; The composite injection combustion device is installed on the ladle baking furnace body and is used to inject the main combustion gas, oxygen and two-phase injection medium formed by biomass and CO2 carrier gas into the combustion zone inside the ladle. The gas supply system, biomass supply system, oxygen supply system and CO2 supply system are respectively connected to the corresponding inlets of the combined injection combustion device; The detection system is used to detect the temperature inside the ladle and the composition of gases in the combustion zone; The control system is connected to the detection system and each supply system to perform phased closed-loop regulation of the flow rate of each injection medium based on the temperature and gas composition signals fed back by the detection.

[0088] The ladle baking furnace body is the ladle baking station mentioned in step S0 of the aforementioned embodiments, used to provide a closed baking space and thermal environment. In these embodiments of this application, the ladle baking furnace body can be set as a semi-closed or fully closed cylindrical structure with an open top, lined with refractory material, and equipped with a liftable ladle cover on the top. This furnace body provides the physical carrier for the ladle baking station in the aforementioned method. Its semi-closed structure, combined with the adjustable opening of the exhaust port, adapts to the atmosphere requirements of different baking stages: a large opening for rapid dehumidification in the initial stage, and a reduced opening in the middle and later stages to maintain CO2 concentration and enhance radiation, matching the staged control of steps S0-S4.

[0089] The composite injection combustion device is fixedly installed at the center of the ladle cover. It has oxygen injection channels, gas injection channels, and biomass and CO2 carrier gas mixing injection channels arranged coaxially from the inside to the outside, with the outlet end faces of each channel distributed in a stepped manner. This device is the core component for realizing the aforementioned method of "injecting the main combustion gas, full oxygen or oxygen-enriched gas, and biomass transported by CO2 carrier gas into the combustion zone inside the ladle". Its layered structure ensures that oxygen and gas are mixed and burned first to form a high-temperature core zone, and then the biomass-CO2 two-phase flow is injected. The temperature gradient is used to achieve staged combustion, which avoids backfire and ensures that CO2 can perform its dual functions as a carrier gas and thermal conditioning medium.

[0090] The gas supply system, biomass supply system, oxygen supply system, and CO2 supply system are connected to their respective inlets via pipelines to the combined injection combustion device. The gas supply system includes a storage tank, pressure reducing valve, flow meter, and regulating valve, providing natural gas or converter gas. The biomass supply system includes a sealed silo, variable frequency feeder, and conveying pipeline, providing solid carbon powder. The oxygen supply system includes oxygen generator or liquid oxygen storage tank, vaporizer, and regulating valve, providing pure oxygen or oxygen-enriched gas. The CO2 supply system includes a storage tank, pressure reducing device, and flow distribution valve, providing carrier gas and regulating medium. These four systems work together to achieve staged flow regulation of each medium in the aforementioned method, providing the material basis for the dynamic proportioning control in steps S1-S4.

[0091] The detection system includes multi-point thermocouples arranged at different heights inside the ladle lining and an oxygen volume fraction detector installed in the combustion zone, which collects temperature and gas composition signals in real time. The detection data of this system is directly input into the control system, providing feedback for the oxygen concentration triggering conditions of biomass injection in step S1, the stage transition temperature determination in steps S2-S3, and the closed-loop control of the entire process.

[0092] The control system is connected to the flow control valves of the detection system, the gas supply system, the oxygen supply system, the biomass supply system, and the CO2 supply system. This control system incorporates the staged program and control algorithm described above. Based on the temperature and gas composition signals from the detection feedback, it performs staged closed-loop adjustment of the flow rate of each injection medium, automatically executing steps S0-S4 for full-process control, achieving tracking and matching of the preset ladle baking curve.

[0093] During operation, all components work in a coordinated and interconnected manner: the detection system senses the status → the control system calculates and makes decisions → each supply system performs adjustments → the composite injection combustion device implements injection → the ladle baking furnace maintains the environment. This system architecture transforms the phased dynamic control in the aforementioned method into a physical realization, ensuring the operability and reliability of the technical solution.

[0094] Compared to related technologies, traditional devices are mostly simple structures using a single fuel and a single combustion medium, lacking multi-medium integration and intelligent control capabilities, and unable to achieve coordinated regulation and phased dynamic control of oxygen-biomass-CO2. This solution, through modular system design and signal connection relationships, provides a complete hardware platform for the low-carbon and refined processing of ladle baking.

[0095] In some embodiments, the composite injection combustion device adopts one of the coaxial, layered, or annular injection structures, and is located at the center of the ladle cover, with its nozzle axis aligned with the center line of the ladle.

[0096] A layered structure is the preferred form, featuring three coaxially arranged injection channels: an inner oxygen injection channel, a middle gas injection channel, and an outer biomass and CO2 carrier gas mixing injection channel. This structure is highly compatible with the combustion organization requirements of steps S1-S4: In the preparation and initial heating stages of steps S0-S1, the inner oxygen and middle gas mix and burn to establish a stable flame, while the outer channel is prepared or operates at a low flow rate; in the enhanced baking stage of step S2, all three channels work together at full load, with the outer layer forming a high-radiation carbon powder flame from a high proportion of biomass-CO2; in the isotherm and final stages of steps S3-S4, the outer layer is gradually reduced while the inner and middle layers are optimized to achieve a smooth transition. This layered and orderly structure avoids the flow field turbulence and combustion instability caused by direct mixing of multiple media.

[0097] Positioned at the center of the ladle cover, with the nozzle axis essentially aligned with the ladle's centerline, the flame is symmetrically distributed along the ladle's geometric center, directly serving the technical objectives of "uniform temperature adjustment of the ladle lining" described in step S3 and "enhancing the radiative heat transfer effect of the ladle lining" described in step S2. The distance from the nozzle to the bottom lining of the ladle is set according to the ladle's capacity, ensuring the combustion flame is fully expanded radially and axially within the ladle, achieving uniform coverage of the lining surface.

[0098] The stepped distribution of the outlet faces of each channel (inner layer protruding, middle layer intermediate, outer layer flat or slightly concave) creates a hierarchical combustion organization in physical space: oxygen in the inner layer mixes and ignites with the fuel gas in the middle layer in the protruding area, forming a high-temperature core zone; biomass-CO2 in the outer layer is injected into the rear area, entering the established high-temperature field but avoiding direct contact with the ignition zone, thus ensuring stable ignition and preventing backfire. This spatial arrangement corresponds to the control logic described in step S1, which states that "biomass injection is triggered when the oxygen volume fraction decreases to 0.5%-1.5%", ensuring the safety of biomass injection at both the physical structure and control strategy levels.

[0099] In the coordinated operation of the apparatus and method, the positional accuracy of this structural form directly affects the technical effect of the aforementioned method: excessive centering deviation will lead to flame skewing and uneven heating of the lining, affecting the temperature uniformity adjustment effect in step S3; improper nozzle distance will lead to insufficient flame coverage or excessive scouring, affecting the radiative heat transfer efficiency and lining life in step S2. Therefore, this structural form and positional arrangement are the physical guarantee for achieving the technical objectives of the aforementioned method.

[0100] Compared to related technologies, traditional combustion devices are mostly simple single-channel burners or random mixing and spraying of multiple media, which easily leads to problems such as flow field interference, flame deflection, and uneven heating, and cannot support the precise requirements of staged dynamic control. This solution, through specific structural optimization and precise positioning, provides a reliable hardware foundation for the efficient, uniform, and safe operation of ladle baking.

[0101] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for baking biomass using a steel ladle with oxygen-CO2 injection, characterized in that, The main combustion gas, oxygen-rich or oxygen-enriched gas, and biomass transported by CO2 carrier gas are injected into the combustion zone inside the steel ladle. The process is dynamically controlled in stages based on the temperature of the ladle lining and the oxygen volume fraction in the combustion zone, and includes the following steps: During the heating phase: the main gas injection flow rate is gradually increased from 50%-70% of the design maximum flow rate to 100%. When the oxygen volume fraction in the combustion zone decreases to 0.5%-1.5%, biomass is injected into the combustion zone at a preset initial amount using CO2 as the carrier gas, and the oxygen volume fraction in the oxygen-enriched gas is 80%-100%. Enhanced baking stage: After the temperature of the ladle lining reaches 600℃-750℃, reduce the main gas injection flow rate to 40%-70% of the design maximum flow rate, increase the biomass injection rate to 70%-100% of the maximum value, so that the heat of biomass combustion accounts for 20%-60% of the total heat supply in the combustion zone, and enhance radiative heat transfer by increasing the proportion of biomass injection to form a carbon particle suspension flame with high radiation intensity. Temperature equalization stage: When the temperature of the ladle lining is close to the target baking temperature of 1000℃-1100℃, gradually increase the main gas injection flow rate to 70%-100% of the design maximum flow rate, while reducing the biomass injection rate to 0-60% of the maximum value, and simultaneously reduce the CO2 carrier gas injection flow rate to achieve uniform and stable temperature of the ladle lining.

2. The method according to claim 1, characterized in that, The CO2 serves as both the carrier gas for biomass and the thermal conditioning medium in the combustion zone. It is used to: form a stable two-phase flow with biomass during the injection process to achieve stable transport; and regulate the peak flame temperature and enhance radiative heat transfer in the combustion zone through interaction with the all-oxygen combustion flame.

3. The method according to claim 2, characterized in that, The duration of the enhanced baking stage is 20%-40% of the total baking cycle, and during this stage, the peak flame temperature is controlled to not exceed 1600℃ by adjusting the CO2 carrier gas injection flow rate.

4. The method according to claim 1, characterized in that, The biomass is injected into the ladle combustion zone in the form of solid carbon powder, and forms a stable two-phase flow injection medium under the action of CO2 carrier gas. The powder-to-gas ratio of the two-phase flow is 0.05-0.25 kg / Nm³.

5. The method according to claim 4, characterized in that, The phased dynamic regulation is achieved through the following heating ratio control, where the biomass heating ratio η is defined as: Among them, m∙ bio H represents the mass flow rate of biomass injected per unit time. bio For the lower heating value of biomass, η burn Q represents the combustion efficiency of biomass in the ladle combustion zone. fuel The heat provided by the combustion of the main gas; During the heating phase, η is controlled at 5%-15%; during the enhanced baking phase, η is controlled at 20%-60%; and during the temperature equalization phase, η is controlled at 0%-30%.

6. The method according to claim 5, characterized in that, The CO2 carrier gas injection flow rate is adjusted in conjunction with changes in the biomass injection rate to maintain a constant powder-to-gas ratio in the two-phase flow or to vary along a preset curve. The adjustment follows the formula below: Among them, V∙ co2 V∙ is the CO2 carrier gas injection flow rate, k is the powder-to-gas ratio coefficient, and V∙ base Based on the basic traffic.

7. The method according to claim 1, characterized in that, In the initial stage of heating, the main gas injection flow rate is controlled at 50%-60% of the maximum design flow rate, the oxygen injection flow rate is controlled at 60%-80% of the maximum design flow rate, the CO2 carrier gas injection flow rate is controlled at 30%-50% of the maximum design flow rate, and the biomass injection channel is kept closed to establish a low oxygen concentration environment and prevent the lining from heating up rapidly.

8. The method according to claim 3, characterized in that, The method is applicable to the baking of newly built steel ladles, minor repair steel ladles, or major repair steel ladles. Specifically: the total baking cycle for newly built steel ladles is 72h-108h, with the enhanced baking stage accounting for 25%-35%; the total baking cycle for minor repair steel ladles is 36h-48h, with the enhanced baking stage accounting for 20%-30%; and the total baking cycle for major repair steel ladles is 72h-96h, with the enhanced baking stage accounting for 25%-40%.

9. A ladle-blown oxygen-CO2-biomass roasting apparatus for implementing the method according to any one of claims 1-8, characterized in that, include: Steel ladle baking oven body; A composite injection combustion device is installed on the ladle baking furnace body and is used to inject main combustion gas, oxygen and a two-phase injection medium formed by biomass and CO2 carrier gas into the combustion zone inside the ladle. The gas supply system, biomass supply system, oxygen supply system, and CO2 supply system are respectively connected to the corresponding inlets of the composite injection combustion device; The detection system is used to detect the temperature inside the ladle and the composition of gases in the combustion zone; The control system is connected to the detection system and each supply system, and is used to perform phased closed-loop adjustment of the flow rate of each injection medium based on the temperature and gas composition signals fed back by the detection.

10. The apparatus according to claim 9, characterized in that, The composite injection combustion device adopts one of the following: coaxial, layered, or annular injection structure, and is located at the center of the ladle cover, with its nozzle axis aligned with the center line of the ladle.

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