Coal Mixture pH Control to Preserve Fluidity for Coke Production
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Solution Overview
Problem
Existing methods to inhibit coal weathering, such as using inert gas or coatings, incur high costs and operational expenses, making them economically unfeasible for large-scale coal storage in the ironmaking industry.
Innovation Solution
A method of blending coals to control the pH of adhesion water by adjusting the hydrogen ion release capacity of the coal mixture to 1.2 × 10 -10< (mol/g-coal) or less, using existing facilities to suppress coal fluidity loss without additional capital investment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If inert gas is blown from the bottom of a coal pile to inhibit weathering, then coal fluidity is maintained, but operational costs and gas consumption increase
Solution Approach 1:
The invention utilizes the coal pile itself to generate the protective atmosphere. By controlling the composition of the coal mixture (specifically including coal with high fixed carbon content), the coal pile naturally maintains a low-oxygen environment during weathering, eliminating the need for external inert gas supply systems and operational gas consumption.
Solution Approach 2:
The invention extracts and utilizes the oxygen-consuming property of certain coal types (high fixed carbon content) to create a protective atmosphere. Instead of adding external inert gas, the system uses the coal mixture's own chemical properties to consume oxygen and maintain low-oxygen conditions, thereby preserving coal fluidity without external gas input.
2Stability of the object's composition
If the surface layer of a coal pile is coated to suppress oxygen diffusion, then coal weathering is inhibited, but material costs and operational complexity increase
Solution Approach 1:
The coal mixture itself provides the weathering protection function through its composition. Coals with high fixed carbon content naturally consume oxygen during weathering, creating a low-oxygen environment that protects the coal pile. This eliminates the need for external coating materials and the operational complexity of applying and maintaining such coatings.
3Stability of the object's composition
If coal is stored in water or sealed tanks to prevent weathering, then coal fluidity is maintained, but capital investment increases
Solution Approach 1:
The invention makes the coal pile self-protecting through proper mixture composition. By including coals with high fixed carbon content (30% or more), the pile naturally consumes oxygen and maintains low-oxygen conditions, eliminating the need for expensive sealed storage infrastructure and water storage systems.
Solution Approach 2:
The invention extracts the oxygen-consuming capability from specific coal types and uses it to create a protective atmosphere within the coal pile. This approach replaces the need for capital-intensive sealed storage facilities by utilizing the chemical properties of the coal mixture itself.
4Stability of the object's composition
If heavy equipment is used to compact the surface layer of a coal pile, then oxygen diffusion is suppressed, but operational costs increase
Solution Approach 1:
The coal mixture composition (including high fixed carbon coals) provides natural weathering protection through internal oxygen consumption. This eliminates the need for heavy equipment operations to compact the surface, thereby eliminating the associated operational costs and energy consumption.
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 effectively inhibits coal fluidity loss during storage and transportation, enabling the production of high-strength coke with reduced operational costs.
Implementation Method 1
blending coals to control the pH of adhesion water by adjusting the hydrogen ion release capacity of the coal mixture
Implementation Method 2
Coal fluidity is known to decrease with time because of deterioration due to oxidation in air which is referred to as 'weathering'
Data Source
Figure 1~2
Figure 3
AI summary
Provided is a method for producing a coal mixture in which it is possible to suppress a decrease in coal fluidity better than existing techniques by a simple method. In a method for producing a coal mixture including blending a plurality of coals, formula (1) and formula (2) below are satisfied: [Formula 1] αcalc=∑iNαi×xi αcalc≤1.2×10−10mol/g−coal where, in the formula (1) and the formula (2), αcalc is the hydrogen ion release capacity per unit mass (mol/g-coal) of the coal mixture, αi is the hydrogen ion release capacity per unit mass (mol/g-coal) of a coal i, xi is the blending ratio of the coal i blended in the coal mixture, and N is the total number of brands of coal contained in the coal mixture.