TITLE: Methane Suppression in the Fischer-Tropsch Synthesis: Final Report.

AUTHOR: E. T. Iyagba;   J. U. Nwalor;   T. E. Hoost;   J. G. Goodwin.

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],  31 Jan 88,  50p.

NTIS ORDER NO.: DE88006658/INW

ABSTRACT:

The objective of the project was to investigate the possiblity of modifying methane formation during the Fischer-Tropsch (F-T) synthesis independent from other hydrocarbons by systematically changing catalyst characteristics. It would seem that the best way to decrease methane selectivity is still via the use of catalyst modifiers. In order to 'tailor-make' catalyst surfaces which minimize 'extraneous' methane synthesis without disrupting F-T synthesis, it is necessary for us to fully understand the mechanism(s) by which such modifiers operate. An investigation of F-T synthesis on K- and Cl-modified Ru Catalysts was carried out. The steady-steady reaction results illustrate how chlorine enhances the selectivity of methane formation while potassium decreases it. In order to better understand methane selectivity changes, a detailed study of Cl-modification of Ru catalysts was made. Ammonia synthesis and methanation reaction results on the same series of catalysts (obtained by using the steady-state isotopic transient technique) in addition to the deactivation results for F-T suggest that structural rearrangements induced by the presence of chlorine, rather than selective site blocking or electronic interactions, may be the primary mechanism of chlorine modification of supported ruthenium catalysts. The results of this study indicate that catalyst modifiers may act to change the catalytic properties by inducing certain metal surface structures. This is a mechanism of modification which has, yet, not been addressed in detail. 49 refs., 16 figs., 7 tabs. (ERA citation 13:030166)

REPORT  NUMBER: DOE/PC/70020-T1

CONTRACT  NUMBER: AC22-84PC70020