The nanoscale pore characteristics of coking coals: Part 2 – Optimization of the experimental conditions and calculation methods of pore size distribution

Abstract

In this study, the pore size distribution (PSD) of the same middle rank coking coal was investigated to optimize the experimental conditions and calculation methods. This was to confirm if the optimum of the experimental conditions optimized by the methods with a combination of adsorption and desorption isotherm branches is consistent with the conclusion by the methods only within the adsorption isotherm branch. Furthermore, two different calculation methods (the Barrett-Joyner-Halenda (BJH) and de Boer (DB) methods) within adsorption and desorption isotherm branches which adopted different ideal pore models were adopted. The optimums of sample evacuation time, target temperature, and sample particle size range are consistent with the conclusions in Part 1. However, the optimal sample weight is opposite to the results in Part 1, and then with the analysis which combined with the characteristics of coking coals, the conclusion in Part 1 was considered to be more believable. At last, the optimal experimental conditions for PSD in this article were adopted the same as those for specific surface area and micropore volume in Part 1. Moreover, the optimum calculation methods were disclosed to be the BJH method within the adsorption branch and the DB method within the desorption branch.