Fluid catalytic cracking: Selectivity and product yield patterns

Abstract

Fluid catalytic cracking, a common secondary process employed in the petroleum industry, is used to convert heavier feedstocks into products such as liquefied Petroleum Gas (LPG), motor gasoline, diesel etc. The present study focuses on developing a three lump fraction kinetic model to estimate the yield of C5 up to 370°C cut (motor gasoline and middle distillates). A Micro Activity Test (MAT) apparatus was used to estimate the parameters in the kinetic model. The study is useful in evolving a procedure to simulate plant performance using experimental data obtained in the MAT apparatus for a particular catalyst and feedstock in terms of the product yield pattern.

Estimation of Kinetic Constants of a Five-Lump Model for Fluid Catalytic Cracking Process Using Simpler Sub-models

“…These results agree with those reported in the literature using similar MAT unit and operating conditions …”

A Simple Method for Estimating Gasoline, Gas, and Coke Yields in FCC Processes

“…Hari et al followed a similar procedure to evaluated the combined cracking and decay constants ( k i φ ) with experimental data obtained in a MAT unit at a reaction temperature of 528 °C, WHSV of 10 h -1 , and catalyst-to-oil ratio of 3.65 using a modified 3-lump kinetic model (gas oil: over 370 °C; gasoline and middle distillates: C 5 -370 °C; and coke plus gas). Gasoline plus middle distillates formation and cracking reactions were assumed to be of first-order reaction while gas oil to gas plus coke cracking was considered as a second-order reaction.…”

“…Another important reason that could explain the high deviations obtained by Hari et al is that they assumed first order for gas oil to gasoline and middle distillates reaction.…”

“…Hari et al used a simplified description of the product yield distribution in terms of three lumped components, i.e., the charge material (gas oil: over 370 °C), gasoline and middle distillates (C 5 -370 °C cut), and the remaining coke and gas. The gas oil to gasoline and middle distillates and gas oil to coke and gas reactions were assumed to be of order one and two, respectively.…”