Dimensional Changes of Molecularly Oriented Domains in Coke

Abstract

The following characteristics of molecularly oriented coke domains are investigated as a function of their position within the coke and the distance from the coke oven’s heating wall: their height L_c and width L_a, the interplane distance d₀₀₂, the domain density ρ, and the number of layers N within the domain. It is found that L_c and L_a decrease nonlinearly with increase in the distance from the coke oven’s heating wall. The coke’s structural strength Π_c (State Standard GOST 9521–2017) is greater for positions near the wall than for the central region of the coke. The ash content and chemical composition of coke samples in the >0.1 mm and <0.1 mm size classes are determined after crushing in a mill. On the basis of the results of this research and literature analysis, it is established that there is no reliable mathematical model relating the high-temperature characteristics CRI and CSR with the cold mechanical strength M₁₀ and M₂₅. Hence, in broad coke ovens, with constant batch composition, the coke produced may be regarded as of high quality in terms of M₁₀ and M₂₅ but of low quality in terms of CRI and CSR. If the variation in the characteristics of the molecularly oriented domains and the strength of the coke after reaction with CO₂ (CSR) are compared as a function of the distance from the coke oven’s heating wall, it is clear that the parameters L_c, L_a, and d₀₀₂ may be used to create a model capable of predicting CSR.