Melter-Gasifier Fine Coal Injection for Molten Iron Production
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Solution Overview
Problem
The blast furnace method for producing molten iron requires significant preliminary processing of raw materials and generates excessive dust and incomplete pyrolysis of coal, leading to inefficient heat utilization and reduced reduction power of the reducing gas.
Innovation Solution
Injecting fine carbonaceous materials with volatile matters into a melter-gasifier, which form a coal packed bed with lumped carbonaceous materials, allowing for enhanced combustion heat utilization and improved reduction power by controlling the oxidization ratio and grain size of the carbonaceous materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lumped coals are charged into the melter-gasifier and rapidly heated in the dome portion, then the volatile matters are pyrolyzed into reducing gas, but a large amount of dust containing carbon components is generated which deteriorates the permeability of the melter-gasifier
Solution Approach 1:
The invention segments the coal charging process into two distinct paths: lumped coals (6-50mm) are charged into the dome portion for pyrolysis and combustion, while fine coals (0.5-5mm) are injected separately into the lower portion of the melter-gasifier. This segmentation allows the dust generated from lumped coal pyrolysis to be burned by the dust burner without blocking the melter-gasifier, as the fine coals provide additional combustion zone in the lower portion.
Solution Approach 2:
The invention introduces a dust burner as an intermediary device that captures and burns the dust generated from lumped coal pyrolysis before it can deteriorate the melter-gasifier permeability. The dust burner acts as a mediator between the pyrolysis process and the melter-gasifier, converting harmful dust into useful combustion heat.
2Temperature
If extra oxygen is supplied by the dust burner or oxygen burner to prevent temperature lowering during pyrolysis, then the temperature is maintained, but a portion of the reducing gas is burned and the reduction power is reduced
Solution Approach 1:
The invention segments the oxygen supply function between two distinct devices: the dust burner supplies oxygen for burning dust generated from pyrolysis, while the oxygen burner supplies oxygen for burning volatile matters and maintaining temperature. This segmentation prevents excessive oxygen from reaching the reducing gas, preserving its reduction power while still maintaining the necessary temperature.
Solution Approach 2:
The invention implements feedback control where the oxygen burners are controlled based on the temperature conditions in the dome portion. When the temperature drops during pyrolysis, the oxygen burners activate to maintain temperature, but the system monitors to prevent excessive oxygen supply that would burn the reducing gas and reduce its quality.
3Productivity
If the blast furnace method is used with sintering equipment and coke manufacturing equipment, then molten iron can be produced, but heavy investment in additional facilities and equipment leads to increased manufacturing costs
Solution Approach 1:
The invention makes the melter-gasifier a multi-functional device that can perform both pyrolysis/combustion of coals and reduction of iron ores in a single unit. The same melter-gasifier that produces molten iron also generates reducing gas and handles dust combustion, eliminating the need for separate sintering and coke manufacturing facilities.
Solution Approach 2:
The invention merges multiple functions (coal pyrolysis, dust combustion, iron ore reduction, and molten iron production) into a single integrated melter-gasifier system. This consolidation replaces the need for separate blast furnaces, sintering plants, and coke ovens, significantly reducing facility complexity and investment costs.
4Use of energy by moving object
If fine coals are injected into the lower portion of the melter-gasifier, then the combustion heat is enhanced and fuel consumption is minimized, but the grain size must be precisely controlled to ensure proper injection and combustion
Solution Approach 1:
The invention optimizes the grain size parameter of fine coals to a specific range (0.5-5mm) that balances combustion efficiency with injectability. This parameter control ensures the fine coals can be properly injected into the lower portion of the melter-gasifier while maintaining sufficient surface area for rapid combustion and heat release.
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 minimizes fuel consumption, increases the reduction power of the reducing gas, and reduces the amount of CH4 gas, thereby improving the efficiency of molten iron production and reducing operational costs.
Implementation Method 1
Injecting fine carbonaceous materials with volatile matters into a melter-gasifier, which form a coal packed bed with lumped carbonaceous materials, allowing for enhanced combustion heat utilization
Implementation Method 2
The volatile matters contained in the lumped coals are firstly pyrolyzed as a pyrolysis gas having a chain structure of CnHm or as a tar phase having a ring structure
Implementation Method 3
The oxygen is injected into the melter-gasifier through a plurality of tuyeres installed on the outer wall of the melter-gasifier, and burns the coal packed bed
Data Source
AI summary
The present invention relates to an apparatus for manufacturing molten irons by injecting fine carbonaceous materials into a melter-gasifier and a method for manufacturing molten irons using the same. The method for manufacturing molten irons according to the present invention includes steps of reducing mixtures containing iron ores in a reduction reactor and converting the mixtures containing iron ores into reduced materials, preparing lumped carbonaceous materials containing volatile matters as a heating source for melting the reduced materials, charging the lumped carbonaceous materials into a dome-shaped upper portion of a melter-gasifier and forming a coal packed bed, preparing fine carbonaceous materials containing volatile matters as a heating source for melting the reduced materials, injecting oxygen and the fine carbonaceous materials into the coal packed bed through a tuyere installed in the melter-gasifier, charging the reduced materials into the melter-gasifier connected to the reduction reactor and manufacturing molten irons, and supplying reducing gas in the melter-gasifier made from volatile matters contained both in the lumped carbonaceous materials and the fine carbonaceous materials to the reduction reactor.