FCC riser simulation

1 gas-oil inlet -> 1 effluent; reports lump yields, the gasoline optimum and the cat/oil ratio the heat balance demands

Governing equations

The exact equations the solver works for a fcc riser — the same math shown in the app's "Theory" panel, not a black box.

$y_A$

gas-oil lump mass fraction [-]

$y_B$

gasoline lump [-]

$y_C$

light gas + coke lump [-]

$\tau$

catalyst contact time along the riser (2-5 s in practice) [s]

$k_1$

gas oil -> gasoline rate constant (SECOND order in y_A) [1/s]

$k_2$

gasoline overcracking rate constant (first order in y_B) [1/s]

$k_3$

gas oil -> gas + coke rate constant (second order in y_A) [1/s]

$\varphi$

catalyst activity from coke laydown, 1 at the riser inlet [-]

$t_c$

catalyst time on stream [s]

$\alpha$

exponential decay constant [1/s]

$\beta$

power-law decay constant [1/s]

$n$

power-law decay exponent [-]

$C/O$

catalyst-to-oil mass ratio set by the heat balance (5-10 typical) [-]

$\Delta H_{rxn}$

cracking endotherm per kg converted [J/kg]

$x$

gas-oil conversion [-]

$\lambda_{vap}$

feed vaporization enthalpy [J/kg]

$c_{p,oil}$

feed heat capacity [J/kg/K]

$c_{p,cat}$

catalyst heat capacity [J/kg/K]

$T_{regen}$

regenerated-catalyst temperature [K]

$T_{riser}$

riser temperature [K]

$T_{feed}$

feed preheat temperature [K]

Parameters

three-lump fluid catalytic cracking riser (Weekman-form kinetics: second-order gas-oil cracking, first-order gasoline overcracking, time-on-stream catalyst deactivation), reporting the gasoline optimum and the heat-balance cat/oil ratio. Ships NO rate constants: an FCC lump matrix is regressed from a specific feed on a specific catalyst, so you supply your own

Example flowsheets that use it