Hindered Diffusion of Asphaltenes at Elevated Temperature and Pressure Progress Report (open access)

Hindered Diffusion of Asphaltenes at Elevated Temperature and Pressure Progress Report

During this time period, experiments were performed to study the diffusion controlled uptake of quinoline and a coal asphaltene into porous carbon catalyst pellets. Cyclohexane and toluene were used as solvents for quinoline and the coal asphaltene respectively. The experiments were performed at 27 C and 75 C, at a pressure of 250 psi (inert gas) for the quinoline/cyclohexane system. For the coal asphaltene/toluene system, experiments were performed at 27 C, also at a pressure of 250 psi. These experiments were performed in a 20 cm{sup 3} microautoclave, the use of which is advantageous since it is economical from both a chemical procurement and waste disposal standpoint due to the small quantities of solvents and catalysts used. A C++ program was written to simulate data using a mathematical model which incorporated both diffusional and adsorption mechanisms. The simulation results showed that the mathematical model satisfactorily fitted the adsorptive diffusion of quinoline and the coal asphaltene onto a porous activated carbon. For the quinoline/cyclohexane system, the adsorption constant decreased with an increase in temperature. The adsorption constant for the coal asphaltene/toluene system at 27 C was found to be much higher than that of the quinoline/cyclohexane system at the same temperature. …
Date: October 7, 1999
Creator: Guin, James A. & Ramakrishnan, Ganesh
System: The UNT Digital Library
Hindered Diffusion of Asphaltenes at Elevated Temperature and Pressure Progress Report (open access)

Hindered Diffusion of Asphaltenes at Elevated Temperature and Pressure Progress Report

During this time period, we performed experiments to examine the effects of solvent composition on the diffusion controlled uptake of quinoline into alumina catalyst pellets. Of particular interest was the effect of solvent aromaticity on the diffusive uptake process. The uptake experiments were performed at a temperature of 300 C for the adsorptive diffusion of quinoline in a solvent mixture of mineral oil and 1-methyl naphthalene onto alumina catalyst pellets. These experiments were conducted in a 40 cm{sup 3} microautoclave, the use of which is more economical from both a purchasing and waste disposal standpoint due to the small quantities of solvents and catalysts utilized, and is also significantly safer at the higher temperatures. In order to study the effect of aromaticity of the solvent on the hindered diffusion-adsorption process, the experiments were performed at different volume fractions of 1-methyl naphthalene. Detailed calculations were made to estimate the effects of aromaticity, i. e., as reflected by the percentage of 1-methyl naphthalene in the solvent, on the diffusive properties of the solute. Model simulation results were then performed which showed that the mathematical model incorporating diffusion and adsorption mechanisms satisfactorily fitted the adsorptive diffusion of quinoline onto the alumina catalyst at …
Date: April 1, 1999
Creator: Guin, James A. & Vadlamani, Surya
System: The UNT Digital Library