Relationship between refractive indices and other properties of coal hydrogenation distillates

Abstract

The development of new correlations that enable prediction of the physical, chemical, and thermodynamic properties of coal liquids based on simple and modest characterization is important to researchers in coal liquefaction. The present investigation identifies mathematical relationships among refractive index, mid-boiling point, molecular weight, density, and aromaticity of coal-derived distillates.Mathematical equations are obtained that describe relationships among these properties. When compared with those presently in the literature, they appear to be more reliable when used for coal liquids. Two equations are developed that allow the estimation of refractive index of a coal liquid on the basis of measurement of the mid-boiling temperature, molecular weight, and density. One equation is used for coal products having molecular weights less than 200 and another for those having molecular weights 200 or greater. Equations are developed that are useful for the estimation of the molecular weight of coal-derived distillates. An equation is developed that allows estimation of aromaticity on the basis of determination of the atomic hydrogen to carbon ratio and refractive index.This investigation shows that reliable correlations can be developed that fit the measured properties of narrow-boiling-range distillates of coal liquefaction products from various processes and feed coals.Supplementary Material Available: Table IV, the experimentally determined refractive indices at 293 K of the 28 K boiling range distillates from -Coal and Wilsonville along with the values predicted by both eq 1 and 2 as well as the equations of Riazi and Daubert; Table V, average molecular weights determined by VPO, freezing point depression, and LVHRMS for the -Coal distillates; Table VI, experimental molecular weights and those predicted by using a variety of methods; Table VII, experimental aromaticities and those estimated by eq 6 (8 pages).Ordering information is given on any current masthead page.

Light Absorption by Carbonaceous Particles: An Investigative Review

“…These coals also have higher heating values, and are called "high-rank" in coal-science terms. Some optical properties depend linearly on H/C ratio (Ergun and McCartney 1960) or aromatic fraction (White et al 1987). Graphite and coal are both planar; graphite, containing exclusively sp 2 bonds, lies at the most aromatized end of the coal continuum.…”

The Bitumen Upgrading of Nigerian Oil Sand by Supercritical Carbon Dioxide Modified with Alcohols

“…Various methods and techniques of characterization of bitumen fractions obtained by different methods are available in the literature. , In this study, the extracted fractions were analyzed by GC-MS chromatography and by RI measurements, allowing one to calculate different parameters using existing correlations. − …”

“…Measurements of molecular weight or aromaticity can be difficult, time-consuming, and expensive; can require skilled operators; and are often beyond the resources of most small laboratories. The correlations between properties of petroleum liquids and their refractive indices are available in the literature. − Khan has developed several empirical equations to correlate the RI values of the petroleum liquids with the liquid hydrogen content ([H], in weight percent) and the H/C ratio, aromaticity (carbon and proton), molecular weight (MW), density ( d ), and Conradson carbon residue (CCR), which are used in the present work for characterization of the bitumen fractions produced by the SC-CO 2 extraction method. A summary of these correlations with their observed level of significance is given in Table .…”

“…Khan's Correlations Used in This Work for Characterization51 Characterization techniques based upon the liquid's refractive index (RI) are used with petroleum distillates to predict fuel-related properties.…”

“…Characterization of Bitumen Fractions Using Khan's Correlations,51 Based on Their Refractive Indices…”