Study On The Basic Properties Of Coal-derived Liquids

The fundamental research project of coal direct liquefaction on large scale was issued in the 973 PROGRAM in 2004. The second task of the project is research on the basic physical and chemical properties of coal-derived liquids. Based on the determinations of the physical properties of coal-derived liquids, the variation rules for the basic properties would be found and applied to design and operation of the process development unit even of the large scale liquefaction apparatus. Because of the high contents of the aromatic hydrocarbons and the hetero-atoms, such as oxygen, nitrogen and sulfur, so coal liquids are different from petroleum, the existent empirical equations fit for petroleum may be not suitable to the coal-derived liquids. In order to discover the correlations and variations of properties of coal-derived liquids, some of these properties were analyzed and investigated in the thesis.The coal liquid samples were obtained from liquefaction of Shenhua coal and Shengli lignite of Inner Mongolia on continues test plant. The narrow boiling-range fractions were gained by the real boiling distillation. Some basic properties including density, element contents, motive viscosities and saturated vapor pressures of the narrow boiling range fractions were determined, and the relationships between these properties and the average boiling points were summarized. In addition, the relationship between the thermodynamic properties and temperature for every fractions were investigated, the density decrease with temperature rising with a linear relations. Volume expansion coefficients were deduced from the linear coefficients. The dynamic viscosities decrease with temperature rising according with Vogel's equation: Ln(μ)=A+B/(t+C). The saturated vapor pressures increase with the temperature rising according with the Antoine's equation: Ln (P)=A - B /(t+C).The average molecular weight, critical state parameters and acentric factor of the two kinds of coal liquids were calculated as details. Seven relating equations are introduced to calculate the average molecular weight, as a result, recommended formula by Gray et al can procure preferable results. Six equations are chosen to calculate critical...