Direct Reduction Shaft Charging and Discharge Using Vacuum Gas Replacement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for charging and discharging iron ore and sponge iron in direct reduction shafts require large volumes of seal gas, leading to increased capital and operating expenses, and introduce inert gases that accumulate in the process gas, necessitating costly bleeding and environmental emissions.
Innovation Solution
A process involving vacuum evacuation and refilling with process gas from the direct reduction shaft to minimize the need for seal gas, reducing the risk of explosive mixtures and gas accumulation, and utilizing hydrogen as a reducing agent to produce sponge iron.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large volumes of seal gas are used for charging iron ore and discharging sponge iron, then safety against explosive mixtures is improved, but capital and operating expenses increase
Solution Approach 1:
The patent applies inert atmosphere by filling the charging and discharging vessels with inert gas (nitrogen or carbon dioxide) before and during material transfer operations. This creates a safe environment that prevents formation of explosive mixtures between process gas and air, while requiring significantly less seal gas than complete system pressurization methods
Solution Approach 2:
The patent implements preliminary action by evacuating air from vessels before introducing inert gas and process gas. This pre-preparation of the vessel atmosphere eliminates the need for continuous large volumes of seal gas during operation, as the safe inert atmosphere is established in advance
2Reliability
If large volumes of seal gas are introduced to the shaft, then safety against explosive mixtures is improved, but operating expenses increase due to gas production and handling
Solution Approach 1:
The patent applies self-service by using the process gas itself (hydrogen or carbon monoxide from the direct reduction shaft) as the seal gas source. This eliminates the need for separate seal gas production systems and reduces operating expenses, while the inert nature of the process gas maintains safety against explosive mixtures
3Reliability
If inert seal gas is introduced to the shaft, then safety is improved, but inert gas accumulates in the process gas requiring costly bleeding
Solution Approach 1:
The patent applies extraction by removing the problematic step of introducing large volumes of inert seal gas into the shaft. Instead, inert gas is only introduced into charging and discharging vessels temporarily, then completely removed with the discharged sponge iron. This eliminates inert gas accumulation in the process gas circulation system
Solution Approach 2:
The patent implements preliminary action by establishing inert atmosphere in vessels only when needed for material transfer, then completely removing it afterward. This prevents inert gas from entering and accumulating in the process gas system, eliminating the need for costly bleeding operations
4Reliability
If inert gas is introduced to maintain safety, then safety is improved, but environmental impact increases due to gas emissions
Solution Approach 1:
The patent applies self-service by using process gas (hydrogen or carbon monoxide) from the direct reduction shaft as the seal gas. When this gas is used in charging and discharging operations, it is completely recycled back into the shaft with the discharged sponge iron, creating a closed loop with zero emissions. This eliminates the environmental impact associated with inert gas bleeding and flaring
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
Reduces the need for seal gas, decreases operating expenses, and minimizes environmental impact by avoiding inert gas accumulation and bleeding, while enabling efficient production of sponge iron using renewable energy sources.
Implementation Method 1
evacuating gas from the ore charging vessel by application of vacuum
Implementation Method 2
reduced in a direct reduction (DR) process with a carbonaceous reducing gas to produce sponge iron
Data Source
AI summary
An arrangement and process for charging iron ore to a direct reduction shaft, as well as an arrangement and process for discharging sponge iron from a direct reduction shaft. The processes each include the steps of evacuating gas from a vessel by application of vacuum followed by refilling the vessel with a process gas from the direct reduction shaft. Also provided is a system for the production of sponge iron including such an arrangement for charging iron ore and/or discharging sponge iron. Further provided is a process for direct reduction of iron ore, wherein the process includes introducing a process gas from direct reduction to a direct reduction shaft in conjunction with charging iron ore and/or in discharging sponge iron.