Hindered diffusion of asphaltenes at elevated temperature and pressure. Semiannual report, March 20 - September 20, 1996

The objectives are to: investigate the hindered diffusion of coal and petroleum asphaltenes in the pores of catalyst particles at elevated temperature and pressures; and examine the effects of concentration, temperature, solvent type, and pressure on the intraparticle diffusivity of asphaltenes. Progress was made in several areas during this time period. The high temperature/high pressure autoclave has been received from Parr Instrument Company and is in the process of being set up and checked out. During this time period we mainly worked in two areas. In the first area, we performed some measurements on the adsorption isotherms of the model compound quinoline in cyclohexane onto a Criterion 324 catalyst at three temperatures. We are looking at the effect of temperature on the adsorption isotherms of several model compounds. This area is important since the adsorptive uptake of asphaltenes is being studied and the model compound systems lend insight as to how we may expect the more complex asphaltene systems to behave during adsorption on the surface of the porous particles. We found that even for the simple model compound quinoline, the adsorption behavior vs. temperature was quite 0563 complex. The second area explored during this time period was the application of a mathematical model to adsorptive uptake data for asphaltenes on Criterion 324 catalyst particles. This adsorptive uptake data was obtained during the previous time period and was analyzed by mathematical modeling during the current time period. The detailed findings in both of these areas are presented in this report