TITLE: Kinetic Investigations on Fischer-Tropsch Synthesis with Suspended Catalysts.

AUTHOR: R. Kokuun.

INST.  AUTHOR: Oldenburg Univ. (Germany, F.R.). Fachbereich 9 - Chemie.

LANGUAGE: German

PUB.  TYPE: Technical Report

PUB.  COUNTRY: Germany Federal Republic

SOURCE: Department of Energy [DEE],  17 Dec 85,  114p.

NTIS ORDER NO.: DE86770151/INW

ABSTRACT:

The kinetics of the Fischer-Tropsch synthesis on suspended catalysts was studied in a gradientless reactor under exclusion of any mass transfer limitations. A K promoted precipitated Fe catalyst and a Fe/Mn matrix catalyst were employed. The measurements were done under variation of temperature, pressure, gas flow rate and H sub 2 /CO inlet ratio (I). On the basis of the comprehensive experimental rate data, which revealed a reasonable reproducibility even for different catalyst charges, a discrimination among rival kinetic models could be achieved. At low values of I (<=0,8) the Fe/K-catalyst has a high activity with regard to the consecutive shift reaction. Under such conditions all the rate data can be described uniformly and consistently by a kinetic law which is based on enol-complex theory and additionly considers competitive chemisorption of CO sub 2 . At higher values of I (>=1) rate inhibition by CO sub 2 is not observable, instead inhibition by chemisorption of product water comes into play. In this case the rate data follow a kinetic expression which can be derived from both the carbide theory and the CO insertion mechanism. When analysing the data obtained from the Fe/Mn catalyst simultaneous adsorption of CO sub 2 and H sub 2 O has to be introduced for describing the data reasonably. However, pressure increase transforms the original catalyst in another modification with drastically different activity and selectivity properties. (ERA citation 11:050268)

REPORT  NUMBER: NP-6770151