INFLUENCE OF PREPARING NANOSCALE SUSPENSIONS METHOD ON ITS PHYSICO-CHEMICAL AND CATALYTIC PROPERTIES UNDER THE CONDITIONS OF FISCHER-TROPSCH SYNTHESIS

Abstract

Methods for the formation of stable iron-containing suspensions that exhibit activity in the conversion of synthesis gas to C5+ hydrocarbons by the Fischer-Tropsch method are proposed. By XRD and DLS methods it was determined that the formation of the Fe2O3 phase with a bimodal particle size distribution of 50 and 295 nm results in the formation of a suspension by the drop thermolysis method − the gradual introduction of the active metal precursor solution into the dispersion medium (mixture of hydrocarbons C19H40-C32H66). Pulsed introduction of the active metal precursor solution (flash-pyrolysis) into the reactor zone leads to the formation of the Fe3O4 phase with a particle size of 91 and 460 nm. By TEM and AFM methods it was established that, regardless of the slurry forming method, large active phase particles are agglomerates of a finer fraction of particles with an average size of 42 nm. The obtained suspensions demonstrated high activity in the Fischer-Tropsch synthesis under the slurry-reactor conditions, however, the degree of CO conversion is slightly higher in the case of the catalytic suspension prepared by the drop thermolysis method. It is shown that the method of forming the suspension significantly affects the fractional composition of the resulting reaction products. In the presence of a suspension obtained by drop thermolysis, the yield of liquid hydrocarbons reaches 130 g/m3, while a high content of C19+ hydrocarbons is observed. The system formed by the method of flash-pyrolysis makes it possible to obtain mainly the gasoline (C5-C10) and diesel (C11-C18) hydrocarbon fractions. It should be noted that the products of the reaction have a high content of unsaturated hydrocarbons, which reaches 55%. Thus, the composition of the final products of FTS can be controlled by the choice of the catalytic suspension prepared method. For citation: Kulikova M.V., Dement’eva O.S., Chudakova M.V., Ivantsov M.I. Influence of preparing nanoscale suspensions method on its physico-chemical and catalytic properties under the conditions of Fischer-Tropsch synthesis. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 9-10. P. 70-75