DRI Shaft Reduction Using Plasma-Derived Hydrogen
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Solution Overview
Problem
Existing methods for manufacturing Direct Reduced Iron (DRI) are CO2-intensive and require costly catalysts that are sensitive to impurities, leading to reduced yield and environmental impact.
Innovation Solution
A method involving the use of plasma torches to convert methane into hydrogen and solid carbon, combined with a recycling loop for top gas and optional carbon sources like biogas and bio-coal, utilizing CO2-neutral electricity from renewable sources to reduce iron ore in a DRI shaft, maintaining a controlled carbon content in the DRI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If catalytic reforming of natural gas is used to produce reducing gas, then hydrogen and carbon monoxide are produced for iron oxide reduction, but the process requires costly catalysts that are sensitive to impurities and high temperatures
Solution Approach 1:
The patent extracts and removes the catalyst from the reforming process, replacing it with a plasma torch. This eliminates the catalyst's sensitivity to impurities while maintaining the production of hydrogen and carbon monoxide through plasma-driven reforming of natural gas or biogas.
Solution Approach 2:
The patent replaces the chemical catalytic system with a plasma-based system. The plasma torch provides the necessary energy for reforming without requiring catalysts, thus eliminating the reliability issues associated with catalyst poisoning by impurities.
2Quantity of substance
If catalytic reforming is used to produce reducing gas, then hydrogen and carbon monoxide are generated, but the process requires high temperatures above 1100 K
Solution Approach 1:
The patent replaces thermal catalytic reforming with plasma-driven reforming. The plasma torch provides localized high-energy zones that can achieve reforming at lower bulk temperatures, reducing the overall operating temperature requirement while maintaining effective hydrogen and carbon monoxide production.
3Productivity
If traditional blast furnace method is used to produce pig iron, then iron oxides are reduced using coke, but significant quantities of CO2 are released
Solution Approach 1:
The patent changes the chemical composition parameters of the reducing gas by incorporating biogas (rich in methane) and adjusting the H2/CO ratio. This allows for more efficient reduction reactions that produce less CO2 per unit of iron reduced, while maintaining high productivity through optimized gas composition and plasma enhancement.
Solution Approach 2:
The patent converts the harmful CO2 emissions into a benefit by using biogas (which can be derived from organic waste) as a feedstock. The carbon in biogas is already fixed from atmospheric CO2 through biological processes, creating a more carbon-circular system that reduces net emissions while maintaining production efficiency.
4Productivity
If top gas is recycled in the DRI shaft, then reduction efficiency is improved, but gas composition control becomes more complex
Solution Approach 1:
The patent implements a feedback control system where the composition of recycled top gas is continuously monitored and used to adjust the composition of incoming reducing gas. This ensures that the overall gas composition entering the shaft remains within optimal ranges for reduction efficiency, automatically compensating for variations in recycled gas composition.
Solution Approach 2:
The patent designs the gas mixing system to handle multiple gas sources (fresh reducing gas, recycled top gas, biogas) with a single integrated control approach. The system universally manages different gas compositions and flow rates, simplifying control complexity while maintaining reduction efficiency through flexible gas blending.
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
The method achieves CO2-neutral DRI production with high yield and quality, utilizing renewable energy sources effectively and reducing environmental emissions.
Implementation Method 1
A method involving the use of plasma torches to convert methane into hydrogen and solid carbon
Implementation Method 2
Oxygen contained in ores and pellets is removed in stepwise reduction of iron oxides in counter-current reaction between gases and oxide
Implementation Method 3
In this section carburization of the metallized product happens. Carburization is the process of increasing the carbon content of the metallized product inside the reduction furnace
Implementation Method 4
A method involving the use of plasma torches to convert methane into hydrogen and solid carbon, combined with a recycling loop for top gas and optional carbon sources like biogas and bio-coal, utilizing CO2-neutral electricity from renewable sources
Data Source
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AI summary
A method for manufacturing Direct Reduced Iron wherein iron ore is reduced in a DRI shaft by a reducing gas comprising hydrogen obtained by thermal cracking of methane inside a plasma torch, the reducing gas further comprising top gas coming from the DRI shaft and a DRI manufacturing equipment including a DRI shaft (1) and a plasma torch (40), wherein the plasma torch is connected on one side to a methane supply (41) and, on the other side, to the DRI shaft (1), the DRI shaft being provided with a recycling loop allowing to inject its top gas back in the DRI shaft.