Title: Weak interaction between water molecule and different rank coals: a DFT-D3 study

Authors: Yongjin Liao; Zhengyang Gao; Weijie Yang; Jun Zhong; Yi Ding

Addresses: Electric Power Science Research Institute of Guangdong Power Grid Co., Ltd., Guangzhou 510080, Guangzhou, China ' Department of Power Engineering, North China Electric Power University, Baoding 071003, China ' Department of Power Engineering, North China Electric Power University, Baoding 071003, China ' Electric Power Science Research Institute of Guangdong Power Grid Co., Ltd., Guangzhou 510080, Guangzhou, China ' Department of Power Engineering, North China Electric Power University, Baoding 071003, China

Abstract: Weak interaction between water molecules with different rank coals(anthracite, bituminous, subbituminous and lignite) was studied by density functional theory with dispersion correction (DFT-D3) in quantum chemistry method. The equilibrium configurations of water molecule on the surface of coal molecules were optimised, analysis of electrostatic potential on the surface of coal molecule was conducted, and interaction energy between coal molecular surface and water molecular was calculated, as well as interaction types of water on the different rank coals molecular surface were confirmed by calculating the reduced density gradient function (RDG). Research shows that the order of maximum adsorption interaction energy is lignite > subbituminous > bituminous > anthracite, and the hydrogen bond and Van der Waals play a dominant role in the adsorption of water on coal molecule surface. [Received: June 17, 2016; Accepted: March 22, 2017]

Keywords: coal; water adsorption; interaction type; electrostatic potential; RDG analysis.

DOI: 10.1504/IJOGCT.2019.099519

International Journal of Oil, Gas and Coal Technology, 2019 Vol.21 No.1, pp.91 - 108

Received: 24 Jun 2016
Accepted: 22 Mar 2017
Published online: 08 May 2019 *

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