The Interaction Of Coking Coal Pyrolysis Behaviors With The Formation Of Coke Microscopic Pores

The coke pore structure is a factor in determining its mechanical strength and thermal properties,thus affecting the stability and efficiency of the blast furnace.Therefore,exploring the influence of coking coal pyrolysis behavior on pore formation can provide strategies for coke production prediction and regulation of coke pore structured and quality.Ten typical coking coal single coals（coking coal,gas coal,fat coal,1/3 coking coal,lean coal）were chosen as the experimental coals,and one coking coal was chosen as the base coal sample and blended with the remaining nine coals to form the blended coals.The plastic property and thermogravimetric analysis of experimental coals were study by Gieseler plastometry and thermogravimetric analyzer.It was found that the fluidity of the blend coals is not additive,the volatile matter release characteristics of blend coals has a certain degree of additivity,and the degree of additivity decreases with the increase of volatile rate,and the additivity is lowest at the maximum volatile rate(DTG_max).Small-scale dry distillation experiments were conducted on experimental coals to obtain coke.The coke pore structure was tested by microscopic image analysis,and the statistical parameters showed that the average value of five samples can reflect the coke pore structure characteristics.The correlations between the average pore size,average wall thickness of coke and the volatile matter release behavior,fluidity behavior of coal were analyzed.It was found that the average pore size could predicted by using the volatile matter accumulation in the second half of the softening interval(S_mf)of coking coal,the correlation R²of the one-dimensional linear regression is 0.86.The ratio of fluidity accumulation(S_lgf)to volatile matter accumulation in the softening interval(S_vf)of coking coal can predict the average thickness of stomatal walls of coke,and the R²is0.80.Based on the relationship between coke pore structure characteristics and coking coal volatile matter release behavior and fluidity behavior,a mechanism of coke pore structure formation was proposed.The results of this study provide a strategy for predicting and regulating the coke pore structure by combining the thermogravimetric analysis with the Gieseler plastometry using parameters such as fluidity intervals,fluidity accumulation,and volatile matter accumulation.Figure 32;Table 19;Reference 61...