| As the availability of petroleum feedstock becomes uncertain coal liquefaction is expected of a promising way to optimize energy structure and to provide a significant part of the liquid fuels of the future.Several investigation of coal liquefaction are hampered by the unavailability of thermodynamic and physical property data at the reactor running conditions.Nevertheless,these data are essential properties in the reactor design,fractionating towers operation parameters selection,and other process condition optimization.Additionally,the vapor-liquid equilibrium composition of each component would determine not only the size of reactor,but also affect the selection of hydrogen-donor-liquid. Essentially nothing is known about China Shenhua coal liquids.The lack of the basic data reported and the inappropriate applying of the equilibrium data in the literature make us achieve this knowledge of coal liquids.The normal properties such as density,the structure of the coal liquefied oil were gotten by detecting instruments.However,the equilibrium compositions of typical coal liquefiers,which are running at 600～700K and more than 10MPa, are difficult to measure by instruments.The correlation equations are not available way because of the complex of multi-component calculation and the lack of the corresponding parameters.So the simulation software package Aspen Plus which was known for its abundant parameters in the database and its excellent simulation was introduced.This study was supported by the fundamental research project of coal direct liquefaction at large scale(973 PROGRAM).The steps of calculation were as follows:First,the pseudo-components were built up with the COAL-LIQ method based on the physical data of the fractions of coal liquefied distillation oil.And some thermodynamic properties(such as critical properties and acentric factor)were gotten.In order to get the vapor-liquid equilibrium constants under the real liquefaction conditions,the pseudo-components and existing gas,such as H2 and C2H6,were combined together to establish the coal liquefied oil flash distillation system through the Aspen Plus.By using the flash-distillation system, the vapor-liquid equilibrium composition and distribution were calculated at reaction temperature and pressure.Also the rules of equilibrium constant vary with the temperature(623.15～723.15K)and pressure(10～21Mpa)were explored.Furthermore,the parameters of deducing hydrocarbon equilibrium equation at high pressure were regressed.And the two variables vapor-liquid equilibrium equation specified for the Shenhua coal liquefied oil was established. In order to evaluate the quality of the outlet oil efficiently,the calculated cetane index(CI)equations of different compositions were built based on the CI of different flash outlet data at various conditions.Through detection and thermodynamic calculation,the following conclusions can be educed:1,The Shenhua coal liquids are mainly composed of the following materials,alkane,naphthenic hydrocarbons,benzene derivative,phenol, indene,naphthalanene derivative,and so on.Saturated hydrocarbons can be detected in all the fractions.The naphthenic hydrocarbons are mainly in the low temperature fractions.The benzene and its derivatives has the highest content in the fractions about 200℃.The indene,naphthalanene and their derivatives appeared after 220℃.The naphthalanene derivatives and biphenyl accounts for 49.7%in the 280～300℃fraction.2,Tcs of Shenhua coal liquid fractions are proportional to their distilling temperatures(DT).With increase of the DT,pcs increase first,then decreased after 200℃while the Vcs have the different trend.The peak and valley of the pcs and Vcs because of the enrichment of hydroxybenzene in the 180～200℃.3,By using the flash-distillation system,the vapor-liquid equilibrium composition and distribution were calculated at reaction temperature and pressure.In the high temperature separator,some of the fractions were evaporated,and the content decreased with the increase of the distillation temperature.The fractions mainly existed in liquid in the low temperature separator.4,The equilibrium constants(K)of all the compositions had the same trends with the pressure.And the Ks of gases were observably affected by the temperature and pressure.Under 693.15K,the Ks of fractions(higher than 300℃)changed less than 0.025 when pressure increased 10MPa.But the gases and the fractions have different trends when the temperature increased under 15MPa.5,The parameters of deducing hydrocarbon equilibrium equation at high pressure were regressed.And the two variable vapor-liquid equilibrium equation specified for the Shenhua coal liquefied oil was established, ln K1=A+Bp-ln p-Cp/T-D/T-Ep/TF.6,At the range of 300～685K,the density,viscosity,surface tension of the fractions were studied,and the relationships were gotten by regression.7,By nonlinear regression analysis,the relationship between the CI of the compositions with temperature(t)and pressure(p)were obtained.These equations can help to determine the optimal conditions by forecasting the quality of the fractions.
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