Semicoke Surface Tension for Weathered Coal Blending
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for evaluating the weathering degree of coal and its impact on coke strength are limited, particularly when using weathered coal in blends, as they struggle to determine weathering degree and coking property accurately, especially when conventional methods reach their detection limits or when multiple coals are blended.
Innovation Solution
The method utilizes the surface tension of semicoke, prepared by heat-treating weathered coal, as an index to evaluate the weathering degree and control the blending of weathered coal in coal blends, ensuring the strength of coke is maintained by managing interfacial tension and surface tension differences among coal brands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If maximum fluidity MF is used as an index for weathering degree, then it is easy to measure and widely applicable, but it cannot determine weathering degree when MF reaches detection limit or becomes zero
Solution Approach 1:
The patent transitions from using maximum fluidity MF (which reaches detection limit) to using mean maximum reflectance Ro of vitrinite (which maintains measurable range even in weathered coal). This parameter substitution allows continuous weathering degree evaluation across the full range from fresh to heavily weathered coal without hitting measurement ceilings or floors.
2Reliability
If maximum fluidity MF is used as a blending index, then it correlates with coke strength in non-weathered coal, but the correlation breaks down when weathered coal is blended
Solution Approach 1:
The patent replaces maximum fluidity MF with mean maximum reflectance Ro of vitrinite as the blending index. Ro maintains a stable linear correlation with coke strength even when weathered coal is present in the blend, making it universally applicable whether coal is weathered or not, thereby resolving the breakdown of correlation in weathered coal blends.
3Measurement precision
If conventional weathering evaluation methods are used, then they work for non-weathered or lightly weathered coal, but they fail to accurately evaluate heavily weathered coal or coal blends
Solution Approach 1:
The patent makes the evaluation method universal by using mean maximum reflectance Ro of vitrinite, which functions effectively across the entire spectrum from fresh coal to heavily weathered coal and various blend compositions. This single parameter serves multiple purposes: evaluating weathering degree, predicting coke strength, and guiding blending decisions regardless of coal weathering state.
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 allows for the evaluation and control of weathering degree, enabling the addition of weathered coal to blends without decreasing coke strength, by maintaining interfacial tension below 0.03 mN/m and surface tension differences below 1.5 mN/m, thus stabilizing coke production.
Implementation Method 1
determining a surface tension of the semicoke; the weathering degree of the coal is evaluated by using the surface tension of the semicoke as an index
Implementation Method 2
performing a heat treatment on the weathered coal to prepare semicoke
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Provided are, by using an index with which the influence on the strength of coke can be evaluated, a method for evaluating a weathering degree of coal and a coking property of weathered coal within the ranges in which the weathering degree and coking property cannot be determined by using conventional methods, and a method for controlling the weathering degree of coal with which it is possible to add weathered coal to a coal blend to be used for producing coke without decreasing the strength of coke by using the index. The weathering degree of coal is evaluated by using the surface tension of semicoke which is prepared by performing a heat treatment on weathered coal as an index. Moreover, the surface tension of each brand of semicoke which is prepared by performing a heat treatment on each of the plural brands of coal included in coal stock is previously determined. In addition, the proportion of each brand of coal to the whole coal stock is also previously assessed. The weathering degree of each brand of coal is controlled so that the interfacial tension γinter of a semicoke blend which is prepared by blending the plural brands of semicoke in accordance with the proportions is 0.03 mN/m or lower.