Absorber / stripper simulation

gas + liquid -> gas + rich liquid

Governing equations

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

A_i = \frac{L}{K_i V},\qquad S_i = \frac{K_i V}{L} = \frac{1}{A_i}

\varphi_i = \frac{A_i^{N+1} - A_i}{A_i^{N+1} - 1}\quad(\text{Kremser-Souders-Brown};\ \varphi = \tfrac{N}{N+1} \text{ at } A=1)

\dot n_{i,absorbed} = \varphi_i\,\dot n_{i,gas\ in}\quad(\text{stripping mode uses } S_i \text{ on the liquid feed})

A_i < 1 \Rightarrow \varphi_i \to A_i \ \text{as } N\to\infty\quad(\text{a lean-solvent pinch no tray count can beat})

$L$: liquid (solvent) molar flow down the column [mol/s]
$V$: gas molar flow up the column [mol/s]
$K_i$: vapor-liquid equilibrium ratio y/x — how volatile component i is; a *low* K is what makes a component absorbable
$A_i$: absorption factor L/(KV) — the single number that decides recovery; A>1 means the solvent can out-pull the gas
$S_i$: stripping factor, the reciprocal of A — used when the column runs as a stripper
$N$: number of equilibrium stages (trays)
$\varphi_i$: fraction of component i absorbed [0..1] — the Kremser result
$\dot n_i$: component molar flow [mol/s]

n_stages [int >=1], mode ['absorber'|'stripper'], pressure [Pa], temperature [K, optional] — two inlets: a gas and a liquid solvent (Kremser method)