The Pore Structure And Adsorption Ability Of The Sapropelic Organic Matter

The experiments of maceral, maturity, proximate analysis, mercury intrusion, low temperature liquid nitrogen adsorption and isothermal adsorption on the high maturity sapropelic coal collected in Shaanxi province and the low maturity sapropelic coal and humic coal collected in Puxian of Shanxi province, Longkou of Shangdong province and Yaojie of Ganshu province were conducted in this research. The coal petrology and pore structure of sapropelic coal were systematically analyzed. The differences in pores of sapropelic coal and humic coal were compared. Based on the experimental results, this paper analyzed the adsorption capacity of sapropelic coal and the related affecting factors, focused on the adsorption difference of the two types of coals, and the possible reasons of this difference was also discussed.The results of the maceral measurement indicate that the sapropelic coal is distinct in its relativly high content of algae and sclerotinite, with exinite predominating in sapropelic coal while vitrinite in humic coal. The coal proximate analysis shows that the sapropelic coal contains more ash and less water than the humic coal.The experiments of SEM, mercury intrusion and low temperature liquid nitrogen adsorption are contributed to constructing the pore stuctures of the fracture, megalospore, mesopore and micropore. The results show that the pore structures become complicated when the maturity increases, accompanied by the amounts of the micropore increasing and the megalospore and mesopore decreasing. Furthermore, it is found that the development of the micropores focuse on pores with the diameter of 1.5nm and 3.6nm, and the distribution of the micropores evolve from centralization to scattering with the increase in maturity. Besides, this paper illustrates the correlation between pore structure difference and the maceral difference of the two types of coals, which indicates the lower porosity, higher micropore content of the sapropelic coal compared to that of the humic coal.This paper comprehensively analyses the impact of maturity, maceral, water, ash on the adsorption capacity of the sapropelic coal. The research shows that the impact of maturity works with the effects on the moisture content and the pore structure. The change tendency of the adsorptive capacity corresponding to the maturity change is not identical in different coal ranks. In low coal rank phase, although the BET decreases, the adsorptive capacity increases with the maturity increasing due to the sharp decrease of the moisture content, which is the most sensitive factor in this phase. On the other hand, in high coal rank phase, with the sharp decrease of the BET and the slight change in moisture content, the adsorptive capacity decreases with the maturity increasing, which implies that BET is more important than water in this phase.This paper also discusses the correlation between maceral and adsorption. The data analysis show the positive correlation between vitrinite and adsorptive capacity when the inertinite content is low, while the negative correlation between vitrinite and adsorptive capacity when the inertinite content increases. Consequently, it can be estimated that the inertinite whose content is relatively low in the sapropelic coal affect the adsorptive capacity most.In order to compare the adsorption capacity of the sapropelic coal and the humic coal at the same rank, this work refers to pore structure, water, ash as the affecting factors. The results indicate that the sapropelic coal has more developed micropore BET and lower moisture content than the humic coal, but its adsorption capacity is a little lower than the humic coal because of remarkably higher ash content.