Deashing of coal liquids with ceramic membrane microfiltration and diafiltration. Final quarterly technical progress report, October 1--December 31, 1994

Diafiltration experiments were done to determine how much particulate- free oil could be extracted from the solids-containing stream. The 0. 05 {mu}m titania membrane was used for the concentration/diafiltration process runs at 270 C, 80 psig inlet pressure, and 6 gpm crossflow. Five concentration process runs were conducted. After the initial run, the concentrated material was diluted with hydrotreated start-up oil from the final solids back to 10% solids. The concentration was limited by increased pressure drop with increased solids content and plugged membrane module channels. Solids retention was greater than 99.5% for all samples. Attempts to clean membranes with solvent failed due to lack of time. Samples of the permeate and concentrate streams were taken for analysis; the diluent had a similar bp range to the coal liquids in the atmospheric bottoms; thus, distillation could not be used to separate the bottoms from the diluent