TITLE: Separation of Fischer-Tropsch wax from catalyst by supercritical extraction. Quarterly progress report, October 1, 1996--December 31, 1996.

AUTHOR: P. C. Joyce;   M. C. Thies.

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],  1 Jan 97,  11p.

NTIS ORDER NO.: DE97052482INW

ABSTRACT:

One of the major objectives of this research project is to predict the phase behavior of model wax compounds in dense supercritical fluids such as hexane. Because initial results with the SAFT equation have been less promising than expected, the group at North Carolina State University has focused their recent attention on cubic equations of state, in particular the Peng-Robinson and Soave-Redlich-Kwong versions. The focus of this work has been on developing correlations that can be used to predict binary interaction parameters (i.e., k(sub ij)s) for a given binary wax-solvent system. As a first step, k(sub ij)s were first calculated from experimental data on systems containing alkanes between nC(sub 4) and nC(sub 23) at temperatures between 25 and 357(degrees) C. Attempts were then made to correlate these parameters with specific pure component properties of the alkanes of interest. Reasonably good agreement between experimental and predicted k(sub ij)s was found using a correlation that incorporates both temperature and the molecular size of the alkanes. As phase equilibrium data becomes available for higher molecular weight model wax compounds, the ability of the correlation to handle such systems will need to be tested. The phase equilibrium apparatus is currently undergoing modifications that will allow the system to run components that are solids at ambient temperatures. Some problems are still being resolved, as the heavy component tends to precipitate in the sample lines. Modifications have been made that should allow the system to operate reliably.

REPORT  NUMBER: DOE/PC/94219-T9

CONTRACT  NUMBER: FG22-94PC94219