KINETICS OF FISCHER-TROPSCH SYNTHESIS OVER PRECIPITATED IRON CATALYST

The rate of Fischer-Tropsch synthesis was measured in an internallyrecycled gradientless reactor at 230-265℃,1.0-2.6 MPa,H_2/CO feedratios of 1.12-2.41 and space velocity of 300-1.000 h~(-1).The inhibitingeffects of CO_2 and H_2O were determined quantitatively and led to the fullowingtwo rate expressions:-R_(H_2)+co=k_1P_((H_2)~2)P_(co)/(P_(H_2)P_(co)+b_1P_(H_2O)),and-R_(H_2)+co=k_2P_(H_2)P_(co)/(P_(co)+b_2P_(H_2O))where k is the kinetic constant for the rata-determining step and b is a functionof temperature only.The two intrinsic kinetic models were derived from relatedreaction mechanisms.First order with respect to H_2 was also sufficient for thecatalyst,probably due to the low synthesis conversions obtained during the testof this catalyst.Kinetics of the WGS reaction which accounted for waterinhibition under FTS conditions was also investigated.