TITLE: Separation of Fischer-Tropsch wax from catalyst using supercritical fluid extraction. Quarterly technical progress report, 1 October 1995--31December 1995.

AUTHOR: M. C. Thies;   P. C. Joyce.

INST.  AUTHOR: Clemson Univ., SC. Dept. of Chemical Engineering.

SPONSOR: Department of Energy, Washington, DC.

LANGUAGE: English

PUB.  TYPE: Technical Report

PUB.  COUNTRY: United States

SOURCE: Department of Energy [DE],  1996,  8p.

NTIS ORDER NO.: DE96011559INW

ABSTRACT:

The objective of this research project is to evaluate the potential of supercritical fluid (SCF) extraction for separating the catalyst slurry of a Fischer-Tropsch slurry bubble column (SBC) reactor into two fractions: 1) a catalyst-free wax containing less than 10 ppm particulate matter and (2) a concentrated catalyst slurry that is ready for recycle or regeneration. The wax will be extracted with a hydrocarbon solvent that has a critical temperature near the operating temperature of the SBC reactor, i.e., 200-300(degrees)C. Initial work is being performed using n-hexane as the solvent. During the reporting period, work on the small-scale, continuous-flow apparatus continued. Initial experiments have been performed on a binary mixture of n-hexane (solvent) and squalane (model compound) at 200(degrees)C. A total of fifteen samples were collected at 135, 160, and 208 psig, with pressures being controlled to within (plus minus)2 psi. Results indicate that the equilibrium phase compositions can in principle be measured to a reproducibility of (plus minus)0.5% in the squalane-rich bottomphase and (plus minus)2% in the hexane-rich top phase, with respect to the minor component. However, other data measured at these same conditions at another time exhibited scatter that was as much as 5 times greater. We believe that improvements in (1) the method of preheating the feed to the view cell/phase separator and to (2) the sample collection technique are required before data of high accuracy can consistently be generated. The apparatus modifications required to effect these improvements are currently underway and should be completed by the middle of February.

REPORT  NUMBER: DOE/PC/94219-T5

CONTRACT  NUMBER: FG22-94PC94219