Keyvanloo, Kamyar; Fisher, McCallin J.; Hecker, William C.; Lancee, Remco J.; Jacobs, Gary; Bartholomew, Calvin H.

Journal of Catalysis (2015), 327, 33-47 CODEN: JCTLA5; ISSN: 0021-9517. English.

The effects of CO and H2 partial pressures on the deactivation by carbon, in the absence of other deactivation forms, of a CoPt/AlSi Fischer-Tropsch catalyst were investigated during six 800-900 h runs at 230.degree.. Sintering was eliminated by using a catalyst with relatively large Co crystallites; cobalt aluminate formation and oxidation were eliminated by operation at lower conversions and confirmed with TPR and XANES/EXAFS results; and phys. blocking of pores by heavy hydrocarbons was avoided using a large pore support. Both (a) decreasing H2/CO ratio at constant PCO and (b) increasing H2/CO ratio at constant PH2 increase deactivation rate, possibly due to (a) formation of less hydrogenated and (b) more hydrogenated polymeric carbon forms, resp. Deactivation rate was found to increase with increasing polymeric carbon deposition and decreasing CO uptakes of aged catalyst samples. Methane selectivity increases as the catalyst deactivates only for runs at high CO pressures.