Viscosity of Coal-Derived Liquids. 1. A Group Contribution Method for Pure Model Compound Liquids

Abstract

Viscosity of coal-derived liquids is an important property useful in the design of coal liquefaction processes as well as for understanding the flow characteristics of coal liquids. A new model for the prediction of viscosity of coal liquid model compounds has been developed. The model uses Andrade equation with the constants A and B given by a well-defined group contribution method. The group contribution method uses the group definitions, group parameters, and procedure for property calculation, such that all the heteroatom functionalities and some significant molecular structures prevalent in coal-derived liquids are included. The model was tested using experimental data from literature and the average error was determined to be 11.55%. Two of the prominent liquid viscosity models available in the literature were also evaluated using the same experimental data set of coal model compounds. These models could not be applied to all the compounds, as some model parameters were not available. Both the models resulted in errors a few percent higher than obtained from our model, indicating that for coal model compounds the correlation developed here is more widely applicable and more accurate than any other model in the literature. Future efforts will include extension of the correlation to mixtures of coal model compounds and description of a procedure to compute viscosities of appropriately characterized coal-derived liquids.

A Review on Lignin Liquefaction: Advanced Characterization of Structure and Microkinetic Modeling

“…The solubility parameters, calculated using group contributon methods, , for the model monomers and oligomers described previously in Section are given in Table ; their values range from roughly 25–30 MPa 1/2 , in agreement with previously reported values. Values reported for some organic solvents are given in the Supporting Information. , While further detailed review on the calculation of liquid-phase properties relevant to lignin depolymerization is beyond our scope, group contribution methods are capable of estimating other physical parameters in liquids. , Some of these include liquid density, − liquid viscosity, − and surface tension , (of particular interest with respect to bubbling, as in eq and Figure ). Hwang et al have published values for these properties for coal liquids .…”

Extension of a Group Contribution Method to Predict Viscosity Based on Momentum Transport Theory Using a Modified Peng–Robinson EoS

“…The slope of the lineal equation is negative, and the intercept is positive for the four series analyzed. These features suggest that it is possible to develop a generalized model based on group contribution method concepts (GCM). − These facts related to the behavior of the parameters must be checked according to the goodness and robustness of the model from the analysis of their deviations. Based on the linear tendency observed in Figure for parameter δ L (dimensionless), it is supposed that its value can be expressed according to the contribution of each functional group in a molecule, as follows …”