Direct Reduction Reactor Cooling Zone for DRI Storage
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Solution Overview
Problem
Current direct reduction plants require separate cooling vessels for DRI, increasing investment and operational costs, and lack flexibility in seamlessly switching between hot and cold DRI production to meet the needs of continuous and batch-type melting operations.
Innovation Solution
A direct reduction reactor system with an integrated cooling zone within the reactor, allowing for the production of both hot and cold DRI without a separate cooling vessel, using a non-oxidizing gas to cool hot DRI to safe temperatures for storage or immediate use, and diverting means to manage DRI flow based on consumption and storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a separate cooling vessel is used for cooling DRI, then the DRI can be cooled to safe temperatures for storage, but the investment and operational costs increase
Solution Approach 1:
The cooling zone is integrated within the reactor vessel, merging the cooling function with the existing reduction reactor structure. This eliminates the need for a separate cooling vessel and reduces overall system complexity while maintaining the ability to cool DRI to safe temperatures for storage or transport.
Solution Approach 2:
The reactor vessel is designed to serve multiple functions: it performs both the reduction reaction and the cooling of DRI. The same reactor structure that produces hot DRI can also cool it to safe temperatures, making the system more versatile and reducing the need for additional dedicated cooling equipment.
2Adaptability or versatility
If the reactor is designed to produce only hot DRI, then the reactor structure can be simpler, but the flexibility to store DRI for later use is reduced
Solution Approach 1:
The system can dynamically switch between producing hot DRI for immediate melting and cold DRI for storage based on operational needs. The cooling gas circulation can be activated or deactivated to change the discharge temperature, providing operational flexibility without requiring fundamentally different reactor configurations.
Solution Approach 2:
The reactor is designed to universally handle both hot DRI production and cold DRI storage needs. The same reactor structure can discharge hot DRI when immediate melting is required or cool DRI to safe temperatures for storage when production exceeds immediate consumption, making the system adaptable to varying operational demands.
3Temperature
If cold DRI is discharged from a shaft-type reactor, then the DRI can be stored safely, but the reactor design becomes more complicated and may interfere with DRI flow
Solution Approach 1:
The cooling zone is merged with the existing reactor discharge structure, utilizing the lower portion of the reactor vessel that would otherwise be part of the normal discharge path. This integration avoids adding separate cooling equipment that would interfere with DRI flow while still achieving safe discharge temperatures.
Solution Approach 2:
A cooling gas is introduced as an intermediary medium to transfer heat from the hot DRI to achieve safe discharge temperatures. This gas-mediated cooling process occurs within the reactor structure itself, avoiding the need for complex mechanical cooling equipment that would interfere with the gravity-driven flow of DRI particles.
4Productivity
If hot DRI is produced continuously, then the production efficiency is high, but the ability to meet batch-type melting furnace needs is reduced
Solution Approach 1:
The system can dynamically adjust its operation to match the batch-type melting furnace needs. When the furnace is ready for loading, the reactor can discharge hot DRI continuously for high productivity. When the furnace is between batches, the reactor can cool and store DRI, ensuring continuous production capability while adapting to the batch consumption pattern.
Solution Approach 2:
The reactor can perform preliminary cooling of DRI and store it in the cooling zone before the melting furnace is ready for the next batch. This preliminary action ensures that DRI is ready for immediate discharge and melting when the furnace becomes available, maintaining high overall productivity while accommodating batch operations.
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 reduces capital and operational costs, enhances product quality, and allows for flexible operation by eliminating the need for external coolers, enabling efficient integration with both continuous and batch-type melting furnaces while maintaining production during unscheduled shutdowns.
Implementation Method 1
reaction of iron ores (mainly iron oxides) in solid phase with a reducing gas at a high temperature of about 900°C to about 1100°C
Implementation Method 2
circulating a stream of non-oxidizing cooling gas through said cooling zone of the reactor for cooling said hot DRI from said reducing zone down to a safe overall temperature below about 100°C
Data Source
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AI summary
An integrated steelmaking plant design is disclosed for efficiently merging the continuous operation of a reduction reactor producing hot DRI with the batch operation of at least one DRI melting furnace. The direct reduction reactor is adapted for producing hot DRI for its consumption in a DRI melting furnace or for producing cold DRI when the continuous production of DRI will exceed the DRI consumption rate of the melting furnace or when it suffers long-term operational delays. The reduction reactor has a DRI cooling zone within the same reactor vessel which is selectively operable for cooling the DRI in the same reactor vessel when the hot DRI produced in said reactor will not be consumed by the DRI melting furnace and when the capacity of the hot DRI bin feeding the melting furnace is insufficient to accumulate the amount of hot DRI which will not be consumed. The need of a DRI cooling vessel with its associated gas compressor and gas cooling and cleaning system is dispensed with therefore decreasing the capital and operational costs of said steelmaking plant. The invention also allows for a flexible and modular construction and operation of a steelmaking plant and is applicable to reduction reactors whether designed to operate at high or low pressure.