TITLE: Technology development for iron Fischer-Tropsch catalysts.  Quarterly report, April--June 1993.

AUTHOR: B. H. Davis.

INST.  AUTHOR: Kentucky Univ., Lexington. Center for Applied Energy Research.

SPONSOR: Department of Energy, Washington, DC.

LANGUAGE: English

PUB.  TYPE: Technical Report

PUB.  COUNTRY: United States

SOURCE: Department of Energy [DE],  1993,  33p.

NTIS ORDER NO.: DE94002662INW

ABSTRACT:

The Fischer-Tropsch process has attracted a great deal of attention in terms of catalytic activity and selectivity to produce higher number hydrocarbons by reacting carbon monoxide and hydrogen at high pressures in the presence of catalysts. Shortly after the initial discovery, Fischer and Tropsch developed more active catalysts for indirect liquefaction. The product distribution resulting from the Fischer-Tropsch synthesis (FTS) varies widely depending upon the catalysts, the temperature and pressure of reactions, pretreatment conditions, etc. It is desirable to improve the selectivity while maintaining the activity intact. One approach to achieve this task is the addition of promoters such as oxides of K, Mn, Ti, Mo, Ni, and Co, etc. It was observed that most of these promoted catalysts exhibit an increase in selectivity to higher hydrocarbons. For example, the addition of thoria as a promoter to cobalt-kieselguhr catalysts resulted in an enhanced yield of C(sub 5)(sup +) hydrocarbons. Even a small amount of thoria promoter ((approximately)0.4 wt %) addition to Co/ZSM-5 causes a remarkable increase in the conversion, shift activity, and C(sub 5)(sup +) selectivity. Thoria added as a promoter to a precipitated iron oxide catalyst appears to decrease wax selectivity. It is generally believed that the factors such as dispersion effects of rare earth oxides and thoria, the redox properties, and the basic properties of rare earth oxides and thorium oxides, greatly influence the activity and selectivity.

REPORT  NUMBER: DOE/PC/90056-T12

CONTRACT  NUMBER: AC22-91PC90056