Smelt Cyclone Off-Gas Composition Control for High-CO2 Capture
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Solution Overview
Problem
Conventional smelting processes produce off-gases with insufficient CO2 concentration for direct use in carbon capture and storage (CCS) or carbon capture and utilization (CCU), requiring costly and energy-intensive separation measures.
Innovation Solution
Utilize almost pure oxygen and carbon dioxide-containing gases as carriers for feed material injection, combined with hydrocarbon gases for combustion, and employ CO2 as a quenching medium, followed by thorough off-gas cleaning to achieve a CO2 concentration of 80-89%, suitable for CCS and CCU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional hot blast air injection is used in blast furnace ironmaking, then the process can provide necessary heat for melting ores, but the off-gas contains large amount of nitrogen (>50%) which requires costly separation measures for CCS/CCU
Solution Approach 1:
The invention changes the composition parameter of the injection gas from conventional air (approx. 21% O2, 79% N2) to oxygen-enriched gas (30-95% O2). This parameter change eliminates nitrogen from the injection stream, preventing it from contaminating the off-gas and thus enabling direct use of off-gas for CCS/CCU without costly nitrogen removal.
Solution Approach 2:
The invention creates an inert environment by using oxygen-enriched gas instead of air, effectively removing nitrogen (an inert gas in this context) from the system. This allows the off-gas to consist primarily of reactive components (CO, CO2, H2) that can be directly utilized or captured without nitrogen interference.
2Quantity of substance
If oxygen-enriched gas is used instead of hot blast air, then the off-gas CO2 concentration increases, but further separation measures are still required to achieve sufficient purity for direct CCS/CCU use
Solution Approach 1:
The invention optimizes the oxygen content parameter to 30-95% (preferably 50-95%, most preferably 70-95%) to achieve the optimal balance between CO2 concentration in off-gas and process efficiency. This parameter optimization, combined with the carrier gas selection, produces off-gas with CO2 concentration of at least 80%, eliminating the need for complex separation systems.
Solution Approach 2:
The invention uses a composite approach by combining oxygen-enriched gas with specific carrier gases (CO2, H2O, or hydrocarbon gases) to achieve the desired off-gas composition. This composite gas injection strategy produces an off-gas that is inherently suitable for direct CCS/CCU use without requiring additional separation equipment.
3Ease of operation
If standard air is used as carrier gas for feed material injection, then the process is simple to operate, but the off-gas CO2 concentration is diluted and requires energy-intensive separation
Solution Approach 1:
The invention changes the carrier gas composition parameter from standard air (21% O2, 79% N2) to CO2-containing gas or H2O-containing gas. This parameter change prevents nitrogen dilution of the off-gas CO2 concentration while maintaining ease of operation, as the alternative carrier gases are readily available and easy to handle.
4Quantity of substance
If CO2 separation measures are implemented at industrial scale, then sufficient CO2 purity for CCS/CCU can be achieved, but capital investments, operating costs and energy usage increase significantly
Solution Approach 1:
The invention performs preliminary action by pre-configuring the injection gases (oxygen-enriched gas + CO2/H2O-containing carrier gas) to produce off-gas with CO2 concentration of at least 80% directly at the source. This preliminary composition control eliminates the need for subsequent energy-intensive separation processes, achieving both high CO2 purity and low energy consumption.
Solution Approach 2:
The invention converts what would normally be waste gases (CO2-containing carrier gases and oxygen-enriched gas) into a beneficial feature by designing the process to produce off-gas with inherently high CO2 concentration. The gases that would require separation become the means to achieve direct CCS/CCU suitability without additional energy input.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Achieves a high CO2 concentration of 80-89% in the off-gas, enabling direct use for CCS and CCU with reduced capital and operational costs, while minimizing impurities that affect storage and utilization.
Implementation Method 1
an oxygen containing gas is used instead of hot blast, wherein the oxygen will react with injected coals to provide the necessary heat for melting the iron ores and enhancing the chemical reactions
Implementation Method 2
the CO and/or H2 are fully or almost fully utilised by the injected ores and oxygen
Data Source
AI summary
The invention relates to a method for off-gas composition control, wherein the off-gas results from a smelting apparatus for smelting a metalliferous feed material, wherein the smelting apparatus comprises a smelting vessel, a smelt cyclone mounted on the smelting vessel and in connection with the inside of the smelting vessel and an off-gas duct connected to the smelt cyclone, wherein the method provides that an oxygen containing gas containing 95% oxygen or more is injected into the smelt cyclone and that the feed material is injected into the smelt cyclone with a carrier gas other than nitrogen gas.