Closed-Loop Direct Reduction Furnace With Water Vapor Condensation
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Solution Overview
Problem
Existing methods for producing direct reduced metal face inefficiencies in thermal management, hydrogen usage, and carbon emissions, particularly in the production of direct reduced iron, and require scalable solutions for handling metal materials of varying compositions.
Innovation Solution
A closed-loop system with a gas-permeable floor and forced circulation of reducing gas through a furnace space, coupled with a condenser to collect water vapor, maintains pressure and efficiently reduces and carburizes metal materials while minimizing carbon dioxide and carbon monoxide emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrogen atmosphere is used for direct reduction of metal ore, then pure metal is produced, but thermal losses and hydrogen gas usage efficiency are poor
Solution Approach 1:
The patent uses a closed hydrogen atmosphere system where hydrogen serves as both the reducing agent and the inert environment. The charge is heated and reduced in a closed chamber filled with hydrogen gas, preventing oxidation and thermal losses to the surrounding atmosphere. This closed system maintains thermal efficiency while ensuring pure metal production.
2Quantity of substance
If carbon monoxide is used for carburizing metal material, then carbon is provided to the metal, but carbon dioxide and carbon monoxide are released into the atmosphere
Solution Approach 1:
The patent replaces carbon monoxide-based carburizing with a hydrogen-based closed atmosphere system. Carbon is introduced in controlled amounts within the hydrogen environment, and the closed system prevents harmful emissions by containing and recycling the gas atmosphere. This eliminates carbon dioxide release while maintaining effective carburizing of the metal material.
3Productivity
If furnace space is increased to handle large throughput, then productivity increases, but thermal efficiency decreases due to larger volume
Solution Approach 1:
The patent employs pressure control as a key parameter to maintain thermal efficiency in large furnace spaces. By operating under controlled pressure conditions and using forced circulation of hydrogen gas, the system ensures uniform heat distribution and maintains high thermal efficiency even in larger volumes. The pressure regulation allows the furnace to handle large throughput while minimizing thermal losses through optimized gas flow and heat transfer.
4Adaptability or versatility
If metal material is processed in batchwise manner, then flexibility is maintained, but productivity is reduced compared to continuous processing
Solution Approach 1:
The patent implements a semi-continuous batchwise processing system where the charge is heated, reduced, and carburized in sequence within the closed hydrogen atmosphere. The forced circulation system maintains continuous gas flow throughout the process, and the closed system allows rapid cycling between batches. This approach maintains the flexibility of batchwise processing while improving productivity through optimized process sequencing and reduced downtime between batches.
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 system achieves thermally efficient and scalable production of direct reduced metal with low carbon emissions, effectively handling different metal compositions and minimizing gas losses.
Implementation Method 1
heated reducing gas heats said charged metal material to a temperature high enough so that metal oxides present in the charged metal material are reduced, in turn causing water vapour to be formed
Implementation Method 2
a condenser, arranged to condense and collect the water vapour
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
Method for producing direct reduced metal material, comprising the steps: a) charging metal material (142) to be reduced into a furnace space (120); b) providing heat and a reducing gas into the furnace space (120), so that heated reducing gas heats the charged metal material (142) to a temperature high enough so that metal oxides present in the charged metal material (142) are reduced, in turn causing water vapour to be formed; and c) condensing and collecting the water vapour formed in step c in a condenser (280); The method is characterised in that, in step a), the metal material (142) is charged onto a gas-permeable floor (151), in that the reducing gas is circulated in a closed loop upwards through said floor (151), through the charged metal material (142), and further via said condenser (280) and a gas forced circulation device (250), and in that the method further comprises the step d) supplying additional reducing gas to achieve and/or maintain a predetermined pressure in said furnace space (120). The invention also relates to a system.