Configurational diffusion of asphaltenes in fresh and aged catalysts extrudates

Objective is to determine the relation between the size and shape of coal and petroleum micromolecules and their diffusion rates in catalyst pore structures. Diffusivity measurements will be performed with aged catalysts from coal liquefaction pilot plants. During this period, equilibrium adsorption experiments were carried out to determine the adsorption isotherm needed in the data analysis. The equilibrium isotherm for quinoline in cyclohexane with fresh Shell 324 (Ni-Mo/Al[sub 2]O[sub 3]) catalyst was found to be nonlinear and well represented by the Freundlich adsorption isotherm. The effective diffusivity was found to be less than the estimated pore diffusivity for nonrestrictive diffusion, indicating pore restriction for quinoline diffusion in cyclohexane with Shell 324 catalyst

Configurational diffusion of asphaltenes in fresh and aged catalyst extrudates

The objective of this research is to determine the relationship between the size and shape of coal and petroleum macromolecules and their diffusion rates i.e., effective diffusivities, in catalyst pore structures. That is, how do the effective intrapore diffusivities depend on molecule configuration and pore geometry

Studies in coal liquefaction with application to the SRC and related processes. Final report, November 1978-September 1983

The objective of this research program is to systematically investigate, characterize, and delineate the effects of changes in process operating conditions, equipment configuration, and nature of raw materials upon the kinetics, mechanism, and extent of coal dissolution, heteroatom removal, and hydrogenation in the SRC and closely related processes, for the purpose of providing an increased fundamental understanding of SRC process chemistry as well as guidelines and recommendations leading to economic and technical improvements in SRC technology. The program objectives were carried out in cooperation with the Souther Services' SRC pilot plant operation at Wilsonville, Alabama, and with the Rust Engineering subsidiary of Wheelabrator-Frye, Inc. The program is composed of the following 3 tasks: (1) mechanistic studies of coal particle dissolution; (2) catalysis by coal mineral matter; and (3) analytical support. A summary of the most important aspects of the work is presented in this report. Detailed results can be found by referring to the twenty quarterly reports and over thirty technical papers and presentations resulting from work under this contract

Configurational diffusion of coal macromolecules

As shown in last quarter's report on the configurational diffusion of coal macromolecules, the hindered diffusion data for both TPP and coal macromolecules were significantly different from the theoretical correlations. In order to evaluate the factors which could lead to this difference an error analysis was conducted, and the detailed results reported herein. Generally, we did not find any errors which could account for the deviation from the theory, and thus we conclude that this deviation is real and can be ascribed to some factor not considered by the hindered diffusion theory, i.e., attractive or repulsive forces. 2 refs., 4 figs., 4 tabs

Studies in coal liquefaction with application to the SRC and related processes. Quarterly report, May-July 1983

This report examines liquid-phase adsorption as a possible method of studying the interactions between coal liquids and hydrotreating catalysts. The duel purposes of this work are to develop a method to determine specific surface areas of porous catalysts and to examine how compounds commonly found in coal liquids are adsorbed on hydrotreating catalysts. The liquid-phase adsorption studies were performed at room temperature in tubing bomb reactors. Adsorption isotherms obtained from these experiments were assumed to follow Langmuir-type behavior. Compounds used in these studies included PNA compounds, a basic nitrogen containing compound, and an acidic oxygen containing compound. Various commercial grade catalysts as well as presulfided CoMo/Al/sub 2/O/sub 3/ and presulfided iron oxide were used as adsorbents. Experiments have shown that quinoline, a basic nitrogen containing compound, appears to be an excellent compound for surface area determination via liquid-phase adsorption. Adsorption of compounds such as pyrene, a PNA compound, and phenol, an acidic oxygen containing compound, may be used to determine the relative areas of different types of sites on catalyst surfaces. The sensitivity of this liquid-phase adsorption technique was evaluated by adsorbing different solutes on various catalyst surfaces. This technique shows that the adsorptivity of different coal liquids is a distinct function of the individual properties of the adsorbate as well as the properties of adsorbent used. Comparison of the adsorption properties of these coal liquids on various adsorbents may give insights as to how they adsorb on hydrotreating catalysts, how they compete for the active catalyst sites, and what types of sites the adsorbed molecules occupy. 29 references, 37 figures, 41 tables

Improving the quality of deteriorated recycle solvents. Quarterly report, August 1982-November 1982

The overall objective of this work is to identify reasons for solvent degeneration and to determine a feasible mechanism whereby coal-liquefaction processes can be modified to inhibit solvent degradation during the liquefaction process. In this work, the response in product distribution (or oil yield) to different pre-treatment methods was investigated. In related past works, solvent quality was based solely on the amount of standard coal conversion. In this work, solvent quality was also determined with the use of a standard product separation procedure. A brief discussion of related past works is followed up by a discussion of current work in the area of upgrading deteriorated recycle solvents. The effect of solvent pre-treatment on quality during thermal (non-catalytic) and catalytic liquefaction of coal was examined, and a comparison was made. In addition, the effect of the presence of typical compounds found in coal liquids (e.g. pyrene), during solvent pre-treatment, on solvent quality was also investigated. 2 references, 3 figures, 5 tables

Studies in coal liquefaction with application to the SRC and related processes. Quarterly report, May-July 1981

This report discusses a kinetic investigation of the Fe-S-H/sub 2/ system conducted as an outgrowth of current research in the SRC-I (solvent refined coal) process to better understand the effects of naturally occurring iron sulfides in coal hydrogenation and hydrodesulfurization. A total of twelve closed system reactions were carried out in which 48 to 60 mesh pyrite, in the presence of hydrogen gas, underwent transformation to 1C hexagonal pyrrhotite. Reaction temperatures were 350/sup 0/C and 400/sup 0/C with four sample runs at temperature. Initial pressure of hydrogen gas was 1250 psig (8617 KPa). A comparison of the results for each reaction series was evaluated with time and temperature as variables. The transformation rate of pyrite to pyrrhotite was found to increase over the range of reaction temperatures with the 400/sup 0/C samples showing the greatest amount of transformation per unit time. For the 375/sup 0/C and 400/sup 0/C runs pyrrhotite formation decreased after approximately 15 minutes of reaction time due to (1) reduced availability of pyrite, and (2) resistance to diffusion in the topochemical product layer