Analysis of influence of alkali metal catalysis on non-uniform deterioration characteristics of blast furnace coke
With the addition of various low-quality raw materials in the blast furnace,the enrichment of alkali metals increases.And in the context of carbon peaking and carbon neutrality,the reduction in coke usage makes its quality more and more important.In order to elucidate the effect of alkali metal catalysis on the non-uniform dissolution and deterioration characteristics of coke,the relationship between matrix and porosity of alkali metal at different reaction stages of coke was studied by coke powder and block coke dissolution experiments and segmented analysis method.Based on the relative size of the chemical reaction rate and the stomatal diffusion rate of the basic characteristics of coke deterioration,the non-uniform deterioration parameter(kv/Deff)1/2 of coke was further improved and optimized to more accurately describe the non-uniform deterioration behavior of coke in the blast furnace.The results showed that during the dissolution process,there was an obvious reaction gradient in the porous structure of coke,that was non-uniformity.Its size was closely related to the matrix reactivity and pore diffusion characteristics of coke,and alkali metals played a positive catalytic role in matrix reactivity,while the pore diffusion coefficient changed with the random evolution of coke pore structure,and the direct relationship with alkali metals was small.Alkali metal catalysis had a significant kinetic effect on the carbon loss process of coke,it can significantly increase the(kv/Deff)1/2,resulting in the formation of a larger reaction gradient inside the porous structure of coke,reducing the deterioration uniformity of coke.This made the particle size distribution of the coke more uneven after the deterioration of the blast furnace,thus greatly reducing the permeability of the blast furnace.The non-uniform deterioration parameters can provide an effective reference for further constructing the mathematical relationship of the dissolution behavior of blast furnace coke,and provide a reference for future blast furnace production.
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