This tool performs a detailed stage-wise analysis of an absorption column used for gas–liquid mass transfer. It allows the user to evaluate how different components are absorbed from a gas stream into a liquid solvent under equilibrium-controlled conditions. The tool supports multicomponent systems and provides insight into separation efficiency, required number of stages, and the influence of operating parameters.
The user can define gas and liquid flow rates, component compositions, and equilibrium behavior. Based on these inputs, the tool computes operating lines, equilibrium relationships, and stage-by-stage material balances for each component.
The primary objectives of the tool are:
- Analysis of absorption performance for single or multiple components
- Estimation of component transfer between gas and liquid phases
- Evaluation of the effect of flow rates and equilibrium slopes
- Determination of stage-wise compositions along the column
The calculations are based on classical absorption theory under the assumptions of steady state, constant molar flow rates, and linear equilibrium relations.
Material balance for a component across a differential stage:
\[ G \, dy = L \, dx \]
where:
- \( G \) is the gas molar flow rate
- \( L \) is the liquid molar flow rate
- \( y \) is the gas-phase mole fraction
- \( x \) is the liquid-phase mole fraction
The equilibrium relationship between the gas and liquid phases is assumed to be linear:
\[ y^* = m \, x \]
where:
- \( y^* \) is the equilibrium gas-phase mole fraction
- \( m \) is the equilibrium slope for the component
The operating line for absorption is obtained from the overall component balance:
\[ y = \frac{L}{G} x + y_{\text{out}} - \frac{L}{G} x_{\text{in}} \]
where:
- \( y_{\text{out}} \) is the gas outlet composition
- \( x_{\text{in}} \) is the liquid inlet composition
Stage-wise calculations are performed by alternating between the operating line and the equilibrium line. For each stage \( n \):
\[ y_{n+1} = \frac{L}{G} x_n + C \]
\[ x_n = \frac{y_n}{m} \]
where \( C \) is the operating line intercept determined from boundary conditions.
For multicomponent systems, the above equations are applied independently to each component, assuming no interaction between components in the equilibrium relation.
The number of effective stages is determined by iterating the stage calculations until the target outlet composition is reached or the maximum specified number of stages is exceeded.
This tool enables quantitative evaluation of absorption column behavior and provides a clear framework for understanding how equilibrium, flow rates, and feed composition influence separation performance.
