This tool performs a stage-wise analysis of a gas–liquid absorption column based on classical equilibrium-stage theory. It allows users to study how a solute is transferred from a gas phase into a liquid phase across multiple ideal stages under steady-state conditions.
Users can specify inlet compositions of the gas and liquid streams, molar flow rates of both phases, the equilibrium relationship between phases, and the maximum number of stages in the column. The tool evaluates operating and equilibrium lines and applies graphical stage stepping to determine the number of theoretical stages required for the specified separation.
The absorption process is modeled assuming constant molar overflow, linear equilibrium behavior, and counter-current operation.
The equilibrium relationship between gas and liquid phases is expressed as:
\[ y = m \, x \]
where:
- \( y \) is the solute mole fraction in the gas phase
- \( x \) is the solute mole fraction in the liquid phase
- \( m \) is the equilibrium line slope
The operating line for absorption is defined by the overall material balance:
\[ y = y_{\text{in}} - \frac{L}{G} \left( x - x_{\text{in}} \right) \]
where:
- \( y_{\text{in}} \) is the solute mole fraction in the inlet gas
- \( x_{\text{in}} \) is the solute mole fraction in the inlet liquid
- \( G \) is the molar gas flow rate
- \( L \) is the molar liquid flow rate
Stage-wise calculations are performed by alternating between the equilibrium line and the operating line. Starting from the top of the column, the liquid composition is obtained from the equilibrium relation:
\[ x_i = \frac{y_i}{m} \]
The corresponding gas composition leaving the stage is determined from the operating line:
\[ y_{i+1} = y_{\text{in}} - \frac{L}{G} \left( x_i - x_{\text{in}} \right) \]
This stepping procedure is repeated until the liquid composition reaches the inlet liquid composition or the specified maximum number of stages is reached.
The number of calculated stages represents the number of ideal equilibrium stages required to achieve the specified absorption performance under the given operating conditions.
This tool provides a clear visualization and quantitative understanding of absorption column design principles and the influence of flow rates and equilibrium behavior on stage requirements.
