Sponge Iron Carburization via Oxygen Injection
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Solution Overview
Problem
Existing methods for producing sponge iron from iron ore using hydrogen-rich process gas struggle with controlling process gas composition and temperature, which affects the carburization process and product quality.
Innovation Solution
The method involves conducting a hydrogen-rich process gas with at least 80 vol.% hydrogen through a first gas line, heating it, and adding carbon dioxide and oxygen to control the temperature and composition, ensuring efficient carburization of sponge iron.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If carbon dioxide is added to the reduction gas to enable carburization, then the carbon content in sponge iron is improved, but the process gas temperature becomes difficult to control
Solution Approach 1:
The patent changes the temperature parameter by injecting oxygen into the reduction gas stream, causing combustion that raises the gas temperature to the required range (700-900°C) for effective carburization. This dynamic parameter adjustment allows control of both temperature and carbon content simultaneously
Solution Approach 2:
Oxygen acts as an intermediary substance that mediates between the carbon dioxide addition and the temperature requirement. The oxygen injection creates a combustion reaction that serves as an intermediate step to achieve the desired temperature condition for carburization
2Productivity
If the flow rate of carbon dioxide is increased to achieve higher carbon content, then carburization efficiency is improved, but temperature fluctuations occur that affect product quality
Solution Approach 1:
The patent implements a feedback control mechanism where oxygen injection rate is adjusted based on the carbon dioxide flow rate and resulting temperature conditions. This feedback loop stabilizes the process gas temperature despite variations in carbon dioxide addition, ensuring consistent product quality
Solution Approach 2:
The system dynamically adjusts the oxygen injection rate in response to changing carbon dioxide flow conditions. This dynamic control allows the system to maintain optimal temperature and carburization efficiency even when operating conditions vary
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
This approach allows for precise control of the process gas temperature and composition, resulting in consistent carburization of sponge iron with a carbon content of at least 1.0 wt.%, enhancing product quality and process reliability.
Implementation Method 1
heating the reduction gas in said first gas line to a first temperature
Implementation Method 2
The addition of the oxygen gas will result in a combustion and increase of temperature of the reduction gas
Implementation Method 3
the carbon dioxide will react with the hydrogen, thereby forming carbon monoxide
Data Source
AI summary
The present invention relates to a method for the production of sponge iron from iron ore, comprising the steps of: charging iron ore into a direct reduction shaft (1); introducing a hydrogen-rich process gas into the direct reduction shaft (1) in order to reduce the iron ore and produce sponge iron; wherein the step of introducing the hydrogen-rich process gas comprises the steps of: conducting a reduction gas comprising at least 80 vol. % hydrogen gas through a first gas line (5) from a hydrogen gas source (4, 21) to the reduction shaft (1), and heating the reduction gas in said first gas line (5) to a first temperature T1. The method further comprises the steps of adding carbon dioxide gas to the reduction gas, upstream or downstream a point along the first gas line (5) at which the reduction gas is heated, and adding oxygen gas to the heated reduction gas to form said hydrogen-rich process gas, and introducing the hydrogen-rich process gas is into the shaft (1).