文摘
Propylene is the unsaturated hydrocarbon emitted to the atmosphere of a coal mine in the process of coal self-heating. Its concentration in mine air is one of the indicators for the assessment of the development of the process of coal self-heating. Coal sorption capacities with respect to propylene may be the reason for the decrease in its concentration in mine air. This may affect the accuracy of the assessment of the self-heating process development, in particular, in the case of coals of considerable sorption capacities. The paper presents the results of coal sorption capacities with respect to propylene performed on 10 samples of bituminous coals acquired from operated coal seams. The sorption capacities of tested coal samples varied depending upon level of metamorphism, porosity, and chemical characteristics of a coal surface. The highest sorption capacities were reported for high-porosity coals of easily accessible pore structure, high specific surface area values, low level of metamorphism, and high oxygen content. The interactions between the electron-donor (and electron-acceptor) centers and 蟺 bond between the carbon atoms of the gaseous reactant probably play the most important role in the sorption of propylene on coals. Coals of low oxygen content, nonpolar surface structure, low porosity, and compact internal structure are characterized by low propylene sorption capacity. The results of the experimental study also indicate the partially irreversible character of the sorption process reflected in the open isotherm hysteresis. Some amount of propylene molecules remains in the coal structure, depending upon the coal properties and the experimental conditions applied.