Influences of chemical structure and physical properties of coal macerals on coal liquefaction by quantum chemistry calculation

Abstract Significant progress has been made in the simulation of coal liquefaction by the quantum chemistry calculation among similar rank coals. Three Chinese bituminous coals from Lingwu, Shendong and Pingshuo were chosen as samples and evaluated. By means of density gradient centrifugation, six kinds of coal macerals with greater than 95% purity were obtained. Using Materials Studio 4.0 quantum chemistry software the hydro-liquefaction activity differences were analyzed by the bond orders of six maceral model structures. Calculation results were compared with specific surface area and average pore size data from nitrogen physical adsorption. It showed that the specific surface area of macerals had no direct relation with their liquefaction yield, while their average pore size and liquefaction yield were shown to be positively correlated. Also, chemical bond cleavage activity of coal structure units influenced liquefaction yield. Under the solvent cycle condition, the capacity of coal liquefaction is potentially decided by the efficiency of hydrogenation to stabilize the free radicals, and also by coal pore size. The rapid cycle of solvent increases the liquefaction yield due to more additional fresh solvent added. The chemical structure and physical properties of Shendong coal displayed much better liquefaction capability than other coals examined.

[1]  S. Nosé.  A molecular dynamics method for simulations in the canonical ensemble , 1984 .

[2]  Jonathan P. Mathews,et al.  The molecular representations of coal – A review , 2012 .

[3]  Z.H.U. Yugui.  APPLICATION OF QUANTUM CHEMISTRY CALCULATION TO INVESTIGATION ON COAL STRUCTURE AND REACTIVITY , 2003 .

[4]  A. V. Duin,et al.  The utility of coal molecular models , 2011 .

[5]  J. T. Joseph.  LIQUEFACTION BEHAVIOUR OF SOLVENT-SWOLLEN COALS , 1991 .

[6]  H. Schobert,et al.  Liquefaction reactivity and 13C-NMR of coals rich in barkinite and semifusinite , 2010 .

[7]  Jackson,et al.  Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation. , 1992, Physical review. B, Condensed matter.

[8]  S. G. Gagarin,et al.  New ideas of coal organic matter chemical structure and mechanism of hydrogenation processes , 1990 .

[9]  R. Malhotra,et al.  Mechanisms of hydrogen transfer and bond scission of strongly bonded coal structures in donor-solvent systems , 1987 .

[10]  John H. Shinn,et al.  From coal to single-stage and two-stage products: A reactive model of coal structure , 1984 .

[11]  Oliver C. Mullins,et al.  Molecular size and weight of asphaltene and asphaltene solubility fractions from coals, crude oils and bitumen , 2006 .

[12]  B. Delley.  From molecules to solids with the DMol3 approach , 2000 .

[13]  R. Kandiyoti,et al.  Comment on ‘Molecular size and weight of asphaltene and asphaltene solubility fractions from coals, crude oils and bitumen’ by S. Badre, C.C. Goncalves, K. Norinaga, G. Gustavson and O.C. Mullins; Fuel 85 (2006) 1–11 , 2006 .

[14]  Toshimitsu Suzuki.  Development of Highly Dispersed Coal Liquefaction Catalysts , 1994 .

[15]  H. Shui,et al.  Study on the aggregation of coal liquefied preasphaltene in organic solvents by UV-vis and fluorescence spectrophotometry , 2011 .

[16]  H. L. Lovell,et al.  Dependence of coal liquefaction behaviour on coal characteristics. 2. Role of petrographic composition , 1975 .

[17]  Chunshan Song,et al.  Short contact-time pyrolytic liquefaction of Wandoan subbituminous coal and catalytic upgrading of the SCT-SRC , 1989 .

[18]  J. Pellegrino,et al.  Activity and selectivity of three molybdenum catalysts for coal liquefaction reactions , 1989 .

[19]  K. Xie,et al.  Pyrolysis Mechanisms of Quinoline and Isoquinoline with Density Functional Theory , 2009 .

[20]  I. B. Goldberg,et al.  Radical formation during vacuum drying of Wyoming subbituminous and Morwell brown coals , 1986 .

[21]  Theoretical modeling of coliquefaction reactions of coal and polymers , 1996 .

[22]  S. G. Gagarin,et al.  Rank dependence of coal physico-chemical parameters: 1. Estimation of intermolecular interaction energy by means of structural parameters , 1992 .

[23]  Y. Kamiya,et al.  Hydrogen shuttling effect of azaaromatics in the hydrogenolysis of the diarylmethane , 1989 .

[24]  J. Hower,et al.  Liquefaction characteristics of the three major maceral groups separated from a single coal , 1992 .

[25]  Chun-Zhu Li,et al.  Comparison of thermal breakdown in coal pyrolysis and liquefaction , 1994 .

[26]  R. Kandiyoti,et al.  Liquefaction: Thermal Breakdown in the Liquid Phase , 2006 .