Precise Measurement of the Swelling Coefficient and Kinetic Study of Reduction in Coal Pellets in the Coal Chemical Industry
 
In the modern coal chemical and metallurgical coking industry chain, coal-based pellets serve as a critical feedstock, and their swelling behavior during high-temperature reduction directly affects furnace operational stability, raw-material utilization, and overall production efficiency. The reduction of iron oxides to metallic iron involves multiple complex kinetic stages; phase transformations and microstructural evolution at different reaction stages both induce changes in pellet volume and morphology. As a core evaluation metric, the coefficient of thermal expansion is essential for assessing pellet performance under high-temperature conditions and for optimizing reduction processes. For a long time, conventional analytical methods have struggled to provide full-process visual observation and precise quantification, resulting in a lack of intuitive and reliable data to support the correlation analysis between swelling behavior and reduction kinetics. This has become a major bottleneck in research on feedstock performance and process optimization within the industry.
 
In response to the practical needs in the coal chemical industry for testing the expansion coefficient of coal-based pellets and for correlating multi-stage iron oxide reduction kinetics with pellet expansion behavior, Tianjin Zhonghuan Electric Furnace has introduced a visual deformation analyzer that offers a completely new solution for such research. This instrument overcomes the limitations of conventional testing methods by employing the core technology of the projected-area method. Under high-temperature reduction conditions, it non-contactly, in real time, and continuously monitors changes in the external dimensions and projected area of coal-based pellets, and uses specialized algorithms to accurately quantify the expansion index, thereby fully reconstructing the entire deformation process—from the initial state through each stage of reduction kinetics.
 
In practical applications, this instrument can clearly capture the multi-stage phase transformations occurring during the reduction of iron ore by iron oxide—namely, Fe₂O₃ → Fe₃O₄ → FeO → Fe—while simultaneously recording the expansion rate, expansion magnitude, and morphological changes of the pellets at each stage. This transforms the abstract kinetics of the reduction process into visual, quantifiable, and intuitive data. Based on these precise expansion-index data, researchers can conduct an in-depth analysis of the intrinsic relationships among reaction mechanisms, phase evolution, and expansion behavior across different kinetic stages, thereby identifying the key factors that drive abnormal pellet expansion. This provides a scientifically sound and highly accurate data foundation for optimizing coal-pellet formulations, controlling reduction temperature and atmosphere, and refining furnace and kiln operating parameters.

 
From the perspective of actual customer value, Tianjin Zhonghuan Electric Furnace Visual Deformation Analyzer This solution has addressed the industry-wide challenges in coal chemical processing—namely, the inability to clearly visualize, accurately measure, and effectively analyze pellet expansion. By applying the projected-area method, the expansion index can now be quantified with high precision, thereby lending greater scientific rigor and persuasiveness to studies on the relationship between reduction kinetics and expansion behavior. Moreover, the system’s full-process visual monitoring capability enables the deformation process under high-temperature conditions to be traced and reproduced, significantly enhancing the efficiency of both research experiments and production inspections. With this equipment, enterprises and research institutions can gain a deeper understanding of the high-temperature performance characteristics of coal-based pellets, effectively reducing the risks of furnace caking and blockage caused by abnormal pellet expansion, improving feedstock compatibility and production stability, and providing robust equipment support for technological upgrades and cost reduction and efficiency gains in the coal chemical and metallurgical coking industries.

(The above content has been collected, summarized, and generated by AI for reference only.)