The Effect of Chlorine Modification of Precipitated Iron Catalysts on Their Fischer–Tropsch Synthesis Properties

Abstract

Precipitated iron Fischer–Tropsch synthesis catalysts impregnated with chlorine were prepared and their Fischer–Tropsch synthesis performances were tested in a 1 L stirred tank reactor. The results showed that the chlorine modification had a significant influence on the Fischer–Tropsch synthesis performance of the precipitated iron catalyst. Compared with the catalyst without the chlorine modification, the catalyst containing about 0.1 wt% chlorine was deactivated by about 40% and the catalyst containing about 1 wt% chlorine was deactivated by about 65%. The textural properties, phase, reduction properties, and chlorine adsorption state of the catalysts before and after the Fischer–Tropsch synthesis were characterized. The strong interaction between chlorine and iron in the catalyst hindered the reduction and carbonization of the catalyst, which was the reason for the deactivation of the catalyst caused by the chlorine modification.

An Overview on Dynamic Phase Transformation and Surface Reconstruction of Iron Catalysts for Catalytic Hydrogenation of COx for Hydrocarbons

“…The synergistic effect between FeC x and FeO x also plays an important role in the CO 2 –FTS performance. Iron oxides have proven to be inert for FTS process, but providing abundant oxygen vacancy sites for CO 2 adsorption and activation. , Lu et al investigated CO 2 hydrogenation to olefins and ethanol over Na-promoted Fe 3 O 4 microspheres under different operating pressures (0.5 MPa, 3.0 MPa). It is proposed that CO 2 activation at the carbide/oxide interface is the key to tune the reaction pathway and product selectivity.…”

“…In contrast to alkali metals, Fe species can form electron-deficient structures under the influence of such additives . S and Cl are generally considered poisonous to active phase . However, some studies have shown that the introduction of Cl promoter through different precursors can promote high selectivity toward light olefins.…”

“…127 S and Cl are generally considered poisonous to active phase. 27 However, some studies have shown that the introduction of Cl promoter through different precursors can promote high selectivity toward light olefins. The presence of Cl electronically regulates the Fe nanoparticles, inhibits H 2 adsorption, decreases the surface H/C ratio, and weakens the CO dissociation, resulting in low activity and high olefin selectivity of the catalyst.…”