DRI Conduit Heater Assembly for HDRI Temperature Retention
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Solution Overview
Problem
The challenge in the direct reduced iron (DRI) and steelmaking fields is maintaining and enhancing the temperature of hot direct reduced iron (HDRI) to optimize briquetting and melting processes, as temperature fluctuations lead to decreased compaction density, cementite content, and increased maintenance, while existing methods fail to efficiently address heat losses and carbon retention.
Innovation Solution
Employing induction heating means on feed legs and surge bin discharge designs to maintain HDRI temperature at 715-720°C and preheat it to 1000°C using induction heating coils and carburizing gas, ensuring uniform and intense heating through customized coil configurations and geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If HDRI is transported through feed legs from DRI furnace to processing equipment, then the DRI can be delivered to various processes (briquetting, melting, etc.), but heat losses occur causing temperature to drop from 700-750°C to 550-600°C
Solution Approach 1:
An induction heating system is introduced as an intermediary device in the feed leg to compensate for heat losses. The heating system includes induction coils wrapped around the feed leg conduit, powered by a variable frequency drive that controls the heating intensity to maintain HDRI temperature during transport
Solution Approach 2:
The patent replaces conventional thermal insulation methods with an active induction heating system. Instead of relying solely on passive insulation to maintain temperature, an electromagnetic induction heating mechanism is used to actively replenish heat losses during DRI transport
2Manufacturing precision
If HDRI temperature is maintained at higher levels (700-750°C) for optimal briquetting quality, then briquette density and strength improve, but heat losses increase and energy consumption rises
Solution Approach 1:
The induction heating system incorporates a variable frequency drive that can be adjusted based on temperature measurements and process requirements. This feedback control allows the system to maintain optimal HDRI temperature for briquetting while minimizing energy consumption by only heating to the necessary temperature level
Solution Approach 2:
The patent changes the operational parameters of the feed leg from passive insulation to active induction heating with controllable temperature. By adjusting the heating power and duration, the system optimizes the balance between maintaining HDRI temperature for quality and minimizing energy losses
3Loss of energy
If HDRI cools down in feed legs (temperature drop of about 50°C), then energy losses are reduced, but DRI quality deteriorates with decreased compaction density and cementite content
Solution Approach 1:
The induction heating system acts as an intermediary that prevents quality deterioration by compensating for cooling effects. The heating coils maintain HDRI temperature within the optimal range, ensuring cementite stability and compaction density while allowing some energy loss to occur naturally
4Temperature
If induction heating coils are added to feed legs to maintain HDRI temperature, then temperature stability improves, but device complexity increases
Solution Approach 1:
The induction heating system is designed to serve multiple functions: maintaining HDRI temperature during transport, compensating for heat losses, and providing controlled heating before processing. This multi-functionality justifies the added complexity by delivering multiple benefits from a single system integration
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 stabilizes cementite content, improves briquette quality, reduces maintenance, and enhances melting furnace efficiency by maintaining optimal temperature and carbon levels in HDRI, resulting in higher quality briquettes and improved throughput.
Implementation Method 1
providing a flow of direct reduced iron from the direct reduced iron source to the processing equipment and heating the direct reduced iron as the direct reduced iron flows through the conduit and to the processing equipment
Implementation Method 2
induction heating means on feed legs and surge bin discharge designs to maintain HDRI temperature at 715-720°C and preheat it to 1000°C using induction heating coils
Implementation Method 3
carburizing gas injection can be located downstream or upstream of the coils providing a flow of carburizing gas through the conduit
Implementation Method 4
ensuring uniform and intense heating through customized coil configurations and geometries
Data Source
AI summary
A method of heating direct reduced iron between a direct reduced iron source and processing equipment for the direct reduced iron, comprises providing a conduit heater assembly between the direct reduced iron source and the processing equipment, wherein the conduit heater assembly receives a flow of the direct reduced iron from the direct reduced iron source and heats the direct reduced iron as the direct reduced iron flows through the conduit heater assembly and to the processing equipment.