Ammoniating granulator simulation

recycle granules + slurry + ammonia -> granules (with a size distribution), offgas, excess ammonia

Governing equations

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

$MR_{out}$

granule mole ratio [-]

$MR_{target}$

specified mole ratio [-]

$s$

ammonia slip [-]

$F_{NH_3,react}$

ammonia reacted [mol/s]

$F_{NH_3,fed}$

ammonia drawn [mol/s]

$F$

molar flow [mol/s]

$h$

molar enthalpy, elements at 298.15 K [J/mol]

$Q$

duty, 0 if adiabatic [W]

$H_{gran}$

granule enthalpy [W]

$H_{gas}$

offgas enthalpy [W]

$T$

bed temperature [K]

$F_{H_2O,evap}$

water evaporated [mol/s]

$w_i$

recycle mass fraction in size class i [-]

$d_i$

class size [m]

$\Delta d$

diameter increase of every granule [m]

$\dot m_{out}$

dry solids out [kg/s]

$\dot m_{rec}$

dry recycle in [kg/s]

$RR$

recycle ratio [-]

$\dot m_{rec,dry}$

dry recycle [kg/s]

$\dot m_{new,dry}$

dry new product made [kg/s]

$N\%$

nitrogen grade, dry basis [wt%]

$P_2O_5\%$

phosphate grade as P2O5, dry basis [wt%]

$M_N$

nitrogen atomic weight [kg/mol]

$n_N$

nitrogen [mol/s]

$M_{P_2O_5}$

P2O5 molar mass [kg/mol]

$n_P$

phosphorus [mol/s]

$m_{dry}$

dry granule mass [kg/s]

Parameters

recycle granules + pre-neutralizer slurry + sparged ammonia -> granules at the product mole ratio. mole_ratio [-] (required, ~1.8-1.9 for DAP); temperature [K] (required, the bed's); ammonia_slip [-] (required, measured); duty [W] (default 0, adiabatic: the water evaporated closes the energy balance); psd_edges_m (granule size grid); nucleus_size_m [m] (start-up bed only). New solid layers onto the recycle (equal diameter growth for every size); grade N / P2O5 wt% dry and as-is, recycle ratio and the granule PSD are reported

Example flowsheets that use it