Polyhydric Alcohols as Promising Eco-Friendly Binders for Coal Blend Preparation in Coking Technology

Abstract

The study addresses the problem of the deteriorating quality of the raw material base in the Ukrainian coking industry, which is primarily caused by the increasing proportion of low-caking, high-ash, and high-sulfur coal grades in the charge. This transformation in the composition of the feedstock adversely affects the thermotechnical parameters of the coking process, leading to uneven thermal decomposition of coal components and deteriorating the physico-mechanical properties of the resulting coke, thereby limiting its applicability in blast furnace operations. One of the promising approaches to correcting the technological characteristics of the coal charge is the application of polyvinyl alcohol (PVA) cryogels as a binding and structure-forming component during the partial briquetting of coal. The mechanisms of three-dimensional porous structure formation in PVA cryogels under cyclic freeze-thaw conditions are described, highlighting their water solubility, non-toxicity, excellent film-forming ability, and efficiency in stabilizing dispersed coal particles. Experimental studies are presented to determine the optimal PVA content, freezing regimes, and drying parameters of the briquettes. It has been established that the incorporation of 5–10% PVA ensures the formation of a robust cryogel matrix, which provides the briquettes with enhanced mechanical stability, reduces their brittleness, and prevents structural failure during transportation and charging into coking chambers. The study demonstrates that the use of PVA cryogels compensates for the deficit of high-caking coal grades, improves the homogeneity of the coal charge, intensifies the initial stages of carbonization, and ensures the production of coke with the required operational properties. The obtained results confirm the high efficiency of using PVA as an innovative tool for raw material modification under contemporary industrial and resource constraints, providing a viable strategy to optimize coke quality and overall process performance in modern coking operations.