Monitoring Fluid Cracking Catalyst Deactivation Profile by Equilibrium Catalyst Separation

Abstract

Successful separation of a precoked, equilibrium USY cracking catalyst into fractions of increasing age reveals a deactivation profile that is largely controlled by zeolite dealumination. Precoking is found to aid the density/age separation only for the youngest fractions. The observed change in Ni/V ratio with increasing "Ni age" is indicative of vanadium migration.Catalytic activity, assessed by cumene cracking on separated fractions and also by analysis of residual coke on catalyst fractions, shows a sharp decline with increasing density (age). This rapid loss of initial activity coincides with zeolite dealumination which is largely completed as a slow rate of zeolite destruction is established. Subsequent loss of crystallinity has little additional effect on activity. The associated loss of microporosity leads to an apparent increase in skeletal density with increasing age.Lattice imaging studies by TEM on a "young" fraction showed extensive regions of crystallinity with minimal evidence of crystallite fracturing. By contrast, similar investigations of an "old" fraction, combined with in situ compositional analysis, revealed small "islands" of crystallinity within a "sea" of disordered material that was once crystalline. Fracture lines at crystallite boundaries are absent. Instead, the small USY crystallites within the "old" fraction are in intimate mixture with the collapsed zeolite. Laboratory evaluation of fluidized-bed catalytic cracking (FCC) catalysts is critically dependent upon the method chosen to simulate catalyst deactivation in the commercial FCU. Conventional laboratory deactivations (high-temperature steam 0097-6156/91/0452-0109$09.75/0

Sodium Deactivation of Fluid Catalytic Cracking Catalyst

“…The Ecats were also examined by electron microprobe (Cameca SX50) to determine the Na distribution within a catalyst particle. Some of the Ecats were separated into eight age fractions based on a modified sink/float procedure described in the literature (13,14). Each age fraction was analyzed by ICP, t-plot and zeolite unit cell size (ASTM D3942-91).…”

Resonant Ptychographic Tomography Facilitates Three-Dimensional Quantitative Colocalization of Catalyst Components and Chemical Elements

“…Pristine particles are composed of La-exchanged Y-type zeolite and calcined kaolinitic clay naturally rich in iron. The catalytic activity of FCC catalysts decreases during long-term industrial operation. ,, This decrease in catalytic activity enforces a continuous replacement of catalyst particles, resulting in an annual demand of around 620 kilo tons worldwide.…”

“…The catalytic activity of FCC catalysts decreases during long-term industrial operation. 8,12,13 This decrease in catalytic activity enforces a continuous replacement of catalyst particles, resulting in an annual demand of around 620 kilo tons worldwide.…”

Impact of rare earth concentration and matrix modification in FCC catalysts on their catalytic performance in a wide array of operational parameters

“…• The physical properties of FCC catalyst particles equilibrated in FCC units vary from particle to particle as a function of their residence time in the FCC unit. Beyerlein et al [13] and Palmer et al [14] have shown that the catalytic performance of such equilibrium catalysts are dominated by the younger fractions which may change catalyst ranking in comparison to FCC catalysts without age distribution. • Changing the degree of dealumination via the variation of the deactivation severity rather than the variation of rare earth concentration may also affect mesoporosity and catalytic properties of FCC catalysts.…”