Coal Blending Using Surface Tension Distribution
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Solution Overview
Problem
Current methods for predicting the strength of coke from coal blends are insufficient due to the lack of consideration for the interaction between coal particles, leading to inaccurate predictions and increased costs, especially when using high-cost coals with high mean maximum reflectance and fluidity, and are not convenient for evaluating non- or slightly-caking coals.
Innovation Solution
A method for blending coals that uses surface tension distributions of heated and cooled coal brands as an index to determine the blending ratio, focusing on the standard deviation of surface tension distributions to control the adhesive strength between coal particles, allowing for the production of high-strength coke without increasing raw material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods use weighted average of physical properties to predict coke strength, then the prediction process is simple, but the prediction accuracy is insufficient due to ignoring coal particle interaction
Solution Approach 1:
The patent introduces surface tension as an intermediary parameter to represent the interaction between coal particles during carbonization. Instead of directly measuring complex particle interactions, the patent uses surface tension distribution (characterized by standard deviation) as a mediator that captures the adhesive properties of coal particles. This allows accurate prediction of coke strength while maintaining relative simplicity in the prediction approach.
2Strength
If high-cost coal with high mean maximum reflectance and high fluidity is used to improve coke strength, then the strength of coke increases, but the raw material cost increases
Solution Approach 1:
The patent changes the predictive parameters from conventional physical properties (mean maximum reflectance, fluidity) to surface tension distribution characteristics (standard deviation of surface tension). This parameter change enables the use of lower-cost coal varieties that were previously difficult to evaluate, while still achieving high-strength coke production through optimized blending ratios determined by surface tension analysis.
Solution Approach 2:
The patent enables the use of cheaper coal types (non- or slightly-caking coals) that were previously considered unsuitable for high-strength coke production. By using surface tension distribution as the evaluation criterion instead of conventional expensive indicators, the patent allows incorporation of lower-cost coal varieties into the blend while maintaining or improving coke strength.
3Quantity of substance
If non- or slightly-caking coal with poor fluidity is used to reduce cost, then the raw material cost decreases, but the detection sensitivity of fluidity index is reduced making measurement difficult
Solution Approach 1:
The patent fundamentally changes the measurement parameter from fluidity index (which has poor detection sensitivity for non-caking coals) to surface tension distribution. Surface tension can be effectively measured and characterized by standard deviation even for coals with poor fluidity, enabling accurate evaluation and optimization of blends containing low-cost non- or slightly-caking coal varieties.
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 enhances the accuracy of coke strength estimation and flexibility in raw material selection, enabling the production of high-strength coke while reducing costs, and is applicable to low-fluidity coals that are difficult to evaluate with conventional methods.
Implementation Method 1
preparing surface tension distributions of the assumed two or more coal brands subjected to heating to a temperature in the range of 350°C to 800°C and then cooling, calculating a standard deviation (σ1) of a distribution obtained by the weighted average of the prepared surface tension distributions
Data Source
Figure 1~3(b)
Figure 4(A)(a)~4(C)(b)
Figure 5
AI summary
There is provided a method for blending coals for coke production, in which the strength of coke produced from a coal blend serving as a raw material is estimated using a physical property that has not been taken into consideration in the past as an index, so that the method is capable of suppressing an increase in the raw material cost of the coal blend and increasing the strength of coal. Two or more coal brands are blended together to provide a coal blend for coke production. When the two or more coal brands are blended together, the coal brands and the blending ratio of the coal brands are determined using the surface tension of each of the coal brands subjected to heat treatment, the surface tension serving as a control index.