TITLE: Low severity upgrading of F-T waxes with solid superacids.  Quarterly report.

AUTHOR: J. W. Tierney;   I. Wender.

INST.  AUTHOR: Pittsburgh Univ., PA. Dept. of Chemical and Petroleum Engineering.

SPONSOR: Department of Energy, Washington, DC.

LANGUAGE: English

PUB.  TYPE: Technical Report

PUB.  COUNTRY: United States

SOURCE: Department of Energy [DE],  1992,  14p.

NTIS ORDER NO.: DE93008123INW

ABSTRACT:

In the past year, we synthesized a Pt/ZrO(sub 2)/SO(sub 4) catalyst which exhibits high conversions and selectivity for desirable products from long-chain paraffins, such as n-hexadecane, n-dotriacontane(n-C(sub 32)) and a SASOL wax(C(sub 58)-C(sub 64)). The catalyst preparation procedure has been carefully worked out and is reproducible. Isomerization and hydrocracking activities of long-chain paraffins and selectivities to various products were examined under mild conditions: 443 K and 2.5 MPa initial hydrogen pressure. Effects of temperature, pressure, catalyst loading, Pt concentration on n-alkane conversions were studied tounderstand the mechanism on the acid catalyst surface. Upgrading of the alkanes proceeds through initial isomerization followed by (beta)-scission reactions and further isomerizations. Isomerization is favored at low temperature and short reaction times, whereas cracking is favored at higher temperatures or pressures. The hydrogen pressure has a considerable influence on the product distribution. Hydrogen transfer probably proceeds through dissociation of molecular hydrogen to generate pretonic acid sites which cause C-C cleavage. Effect of increasing Pt loadings shows a trend similar to increasing hydrogen pressure. Characterization of the present catalyst demonstrates that catalytic activity depends to a large extent on proper coordination of finely dispersed platinum to strong acid sites as well as on pore size distribution.

REPORT  NUMBER: DOE/PC/91304-T4

CONTRACT  NUMBER: FG22-91PC91304