water gas shift reaction and thermodynamic limitations. ConclusionsThe influence of pore diffusional limitations on the methanol reaction rate was analyzed and quantified for the liquid-phase methanol synthesis process. The rate was found to be very significantly limited by pore diffusion when the pellet-sized copper-based catalyst is used in the liquid phase. The limitation is partly due to the decreased liquid-phase diffusivities and larger penetration depth in the larger catalyst. The effectiveness factors ( ) were compared with the theoretical predictions (?jt) based on generalized effectiveness factor correlations. It was also found that the theoretical approach based on the Thiele modulus can be used as an approximate predictor for the analysis of pore diffusional limitations even in a threephase catalytic system. Direct comparisons of reaction rate data obtained from packed-bed and slurry reactor runs must be used with caution in obtaining the experimental effectiveness factor ( ) when the reactor outlet conditions are different.

Ultraviolet resonance Raman spectroscopy has been used to characterize the polycyclic aromatic hydrocarbon composition of a series of distillates of coal-derived liquids. The UV Raman spectra easily monitor changes in the polycyclic aromatic hydrocarbon composition as a function of distillation temperature. Specific species, such as pyrene, can be determined by judicious choice of excitation wavelength.

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.

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