Experimental investigation for effect of multicomponent inorganic-organic acid solution on pore structure of lignite

Abstract

To study the effect of multicomponent inorganic-organic acid solutions on the pore structure of lignite, acid-treated coal samples were analyzed by the liquid nitrogen adsorption method, scanning electron microscopy, energy dispersive spectrometry and molecular dynamics simulation. First, SEM analysis shows that different multicomponent acid solutions promote the formation of different types of corrosion pores. Second, EDS analysis shows that organic acids can be used as auxiliary acids to reduce the activation energy required for the reaction and promote the dissolution of minerals. In addition, liquid nitrogen adsorption analysis shows that multicomponent acid can significantly improve the connectivity of coal samples, and the hole expansion effect is obvious, which can expand the original micropores in the coal into mesopores and macropores. Finally, molecular dynamics simulation shows that acid molecules can promote more water molecules to act on the coal surface, enhancing the penetration of water and the coal surface.