Direct Iron Ore Reduction With Hydrogen Byproduct Separation
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Solution Overview
Problem
Existing direct reduction processes for producing sponge iron from iron ore do not effectively utilize hydrogen as a byproduct and often recycle it with other components, limiting its potential applications outside the process.
Innovation Solution
A process that separates and processes the discharged gas from the reduction zone to produce hydrogen as a byproduct, which can be recycled, stored, or used externally, while also adjusting the carbon content of sponge iron for further processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogen is recycled with other process gas components, then the reduction process can maintain operation, but the hydrogen cannot be utilized for external applications and its potential value is lost
Solution Approach 1:
The patent extracts hydrogen from the mixed process gas stream using separation units (membrane separators, PSA units, or cryogenic separation) to obtain pure hydrogen for external utilization while recycling the remaining gas components to the reduction process, thereby resolving the contradiction between hydrogen utilization and process continuity
Solution Approach 2:
The process gas handling system is designed to serve multiple functions: providing reduction gas to the reactor, generating sellable/purchasable hydrogen for external use, and maintaining process balance through controlled recycling, thus transforming a single-function system into a multi-functional one that resolves the contradiction
2Adaptability or versatility
If process gas is separated to obtain pure hydrogen, then hydrogen can be used externally, but the process becomes more complex and costly
Solution Approach 1:
The system uses the process gas itself as the feedstock for hydrogen production, with the separation units processing the already-available process gas stream rather than requiring external resources, making the system self-sufficient and reducing the need for additional complex infrastructure
Solution Approach 2:
The patent employs separation technologies that exploit differences in physical parameters (permeability, adsorption characteristics, boiling points) of gas components to selectively separate hydrogen from the process gas, achieving pure hydrogen production through parameter-based differentiation rather than complex chemical processing
3Adaptability or versatility
If carbon content in sponge iron is not adjusted, then the production process is simpler, but the sponge iron may not be suitable for certain further processing applications
Solution Approach 1:
The system implements feedback control by monitoring the carbon content in sponge iron and adjusting the process gas composition and flow rates accordingly, using the separated hydrogen and process gas recycling to maintain optimal carbon levels for different product specifications
Solution Approach 2:
The carbon content in sponge iron is made dynamically adjustable by controlling the ratio of hydrogen to process gas, the residence time in the reduction zone, and the temperature profile, allowing the system to adapt to different product requirements without fundamental process changes
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
Produces hydrogen as a valuable byproduct that can be used in other fields and optimizes the carbon content of sponge iron for efficient further processing, reducing energy demands and enhancing process flexibility.
Implementation Method 1
The direct reduction process comprises carrying out a solid-state reaction in which oxygen is removed from the iron ore. This comprises using gasified carbon and/or natural gas/hydrocarbon-containing compounds and mixtures of the recited combinations especially with hydrogen and/or compounds of carbon and oxygen as reduction gas.
Implementation Method 2
The reduction reactions are as follows: 3(Fe2O3)+{CO}⇄(Fe3O4)+{CO2}, (Fe3O4)+{CO}⇄3(FeO)+{CO2}, (FeO)+{CO}⇄(Fe)+{CO2}
Implementation Method 3
The reduction gas is produced from methane, CO2 and steam in a gas reformer (MIDREX® process). CH4+CO2⇄2CO+2H2, CH4+H2O⇄CO+3H2
Implementation Method 4
Such shaft furnaces allow good passage of cooling gas and reduction gas through the iron ore on account of the underlying chimney effect.
Implementation Method 5
In a second step the produced sponge iron is cooled to temperatures typically below 100° C. using a cooling gas in a cooling zone.
Data Source
AI summary
A process for direct reduction of iron ore to sponge iron is disclosed. The iron ore passes through a reduction zone for reducing the iron ore to sponge iron. A reduction gas is passed through the iron ore in the reduction zone. The reduction gas introduced into the reduction zone comprises at least one compound of carbon and hydrogen and/or at least one compound of carbon and oxygen and/or hydrogen. The process gas discharged from the reduction zone comprises hydrogen and at least one compound of carbon and oxygen and/or at least one hydrogen-containing compound. The process gas is supplied to at least a first process step in which at least one compound of the process gas and/or at least portions of the unavoidable impurities are separated and/or removed. After the first process step the process gas is subjected to processing such that hydrogen is obtained as a byproduct.