Simultaneous Characterization of Coke Microstructure and Mineralogy

摘要

Characterization of coke microstructure and mineralogy is critical to reliably predict the effect of coal properties on coke quality.This paper presents applications of some of the advanced microscopic approaches to characterize complex heterogeneous structure of coke matter.An analytical study was carried out to develop a suitable approach for simultaneous examination of microstructure and mineralogy of coke lumps using optical and scanning electron microscopy.Optical microscopy of the tested cokes showed that the total pore phase area was primarily dictated by larger pores,and was found to be higher for lower strength cokes.Microscopic porosity of cokes was invariably less but consistent with the trend indicated by bulk porosity measurements.The microscopic data was processed using an erosion parameter to estimate coke wall thickness,however the estimated thickness was found to be dependent on the frequency of the application of erosion parameter.SEM porosity values of cokes were consistently lower than the total porosity of cokes based on optical microscopic estimates but indicated a similar trend except one coke.Small pore (0.75mm) phase area rather than total pore area indicated an inverse association with coke strength parameters.The study showed that total porosity of cokes could not reliably distinguish the differences of coke strength.The SEM analysis is shown to quantify coke mineral phases as well as their grain size but requires optimization of mineral database.High reactivity cokes were found to be accompanied by high mineral phase area.The SEM approach is promising option due to simultaneous characterization of microstructure and mineralogy but requires validation using wider range of samples.