Dry De-dusting of Direct Reduction Vent Gas
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Solution Overview
Problem
The existing direct reduction methods for metal oxides, such as the MIDREX® process, face challenges in efficiently utilizing the product discharged with vent gas, particularly iron sponge, and require energy-intensive and cumbersome wet de-dusting processes to manage dust and gas emissions.
Innovation Solution
A method and device for dry de-dusting of vent gas using catalytic conversion or combustion to convert gaseous constituents into CO2 and H2O, allowing for the reuse of iron sponge and reducing the effort associated with dust handling and gas release, by utilizing a product discharge device flushed with seal gas and equipped with dry de-dusting systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If wet de-dusting is used to manage dust and gas emissions, then dust removal efficiency is improved, but energy consumption and process complexity increase
Solution Approach 1:
The patent changes the physical state parameter of the de-dusting process from wet to dry. By using dry de-dusting with catalytic conversion, the system avoids the energy-intensive water heating, pumping, and slurry handling required in wet systems, while still achieving effective dust removal and gas treatment
Solution Approach 2:
The patent replaces the mechanical wet de-dusting system with a chemical-catalytic dry system. Instead of using water-based mechanical separation, the invention employs catalytic converters to chemically transform gaseous constituents, achieving dust and gas management with lower energy input
2Object-affected harmful factors
If wet de-dusting is used to manage vent gas emissions, then gas treatment effectiveness is improved, but apparatus requirements and operational complexity increase
Solution Approach 1:
The patent extracts and treats only the specific gaseous constituents that need conversion, rather than handling the entire vent gas stream through complex wet de-dusting equipment. The catalytic converter selectively targets and transforms harmful gases, simplifying the overall apparatus while maintaining treatment effectiveness
Solution Approach 2:
The patent changes the treatment parameter from physical-chemical wet separation to chemical catalytic conversion. This parameter change eliminates the need for water circulation systems, slurry disposal facilities, and associated complex apparatus, achieving gas treatment through a more straightforward catalytic process
3Loss of substance
If iron sponge is discharged with vent gas, then product recovery is improved, but dust handling effort increases
Solution Approach 1:
The patent replaces mechanical dust handling operations with catalytic conversion processes. By using catalysis to treat the vent gas, the system automatically manages the dust-laden gas stream without requiring manual or mechanically intensive dust collection, separation, and handling operations
Solution Approach 2:
The catalytic conversion system performs self-service by automatically converting gaseous constituents and managing the dust-laden vent gas stream. The process inherently handles the dust recovery and gas treatment without requiring separate, effort-intensive dust handling operations, making the overall system easier to operate
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
Enables the simple reuse of iron sponge in steel production, reduces the need for water management and slurry disposal, and allows for easier handling and processing of vent gas emissions, with reduced energy consumption and apparatus requirements compared to conventional wet de-dusting methods.
Implementation Method 1
the content of at least one gaseous constituent of the de-dusted vent gas is reduced by conversion into CO2 and/or into H2O by catalytic conversion using oxygen O2 and/or H2O in the form of steam
Implementation Method 2
the content of at least one gaseous constituent of the de-dusted vent gas is reduced by conversion into CO2 and/or into H2O by combustion
Data Source
AI summary
A method for direct reduction of metal oxide-containing starting materials to produce metallized material by contact with hot reduction gas in a reduction unit (1), wherein the product of the direct reduction is discharged from the reduction unit (1) by means of a product discharge device (3) which is flushed with seal gas and from which vent gas is drawn and subsequently de-dusted. The vent gas is de-dusted dry and the content of at least one gaseous constituent is reduced by catalytic conversion or combustion. Also, a device for carrying out the method is disclosed.