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Calcimator

Absorption Column Calculator

Design a packed absorption column: calculate diameter, packing height, number of transfer units (NTU), and pressure drop.

Inputs

m³/hr
mol fraction
mol fraction
m³/hr
1/m

Results

Column Diameter

0.49 m

≈ 6 credit cards

Packing Height

1.7 m

≈ 11 smartphones

Number of Transfer Units (NTU)3.09
Height of Transfer Unit (HTU)0.55 m
Pressure Drop85.08 Pa/m
How to Use This Calculator
  1. Enter the Gas Flow Rate in m³/hr and the Inlet and Outlet Gas Concentrations as mole fractions to define the required absorption duty.
  2. Enter the Liquid Flow Rate in m³/hr — the liquid-to-gas ratio controls absorption efficiency and solvent consumption.
  3. Enter Henry's Law Constant (m) for the gas-solvent system at operating temperature — larger values mean less soluble gas and require more transfer units.
  4. Enter the Packing Factor in 1/m from the packing vendor's datasheet (Raschig rings, structured packing, etc.).
  5. Review Column Diameter in meters and Packing Height in meters to size the vessel and estimate capital cost.
  6. Check the Number of Transfer Units (NTU) and Height of Transfer Unit (HTU) to verify sufficient mass transfer capacity.

What each input means

Gas Flow Rate
Volumetric flow rate of the gas entering the column.
Inlet Gas Concentration
Mole fraction of the solute in the inlet gas stream.
Outlet Gas Concentration
Desired mole fraction of solute in the exit gas (must be less than inlet).
Liquid Flow Rate
Volumetric flow rate of the absorbing liquid.
Henry's Law Constant (m)
Henry's Law constant relating gas-phase to liquid-phase concentration (y = m·x).
Packing Factor
Characteristic factor for the column packing type (e.g., Raschig rings ~580, Pall rings ~170).

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Gas Flow Rate = 1000, Inlet Gas Concentration = 0.05, Outlet Gas Concentration = 0.005, Liquid Flow Rate = 2000 = 6 input(s) provided
  2. Calculate Column Diameter
    Column Diameter = Math
    0.486 = 0.486
  3. Calculate Packing Height
    Packing Height = Math
    1.702 = 1.702
  4. Calculate Number of Transfer Units
    Number of Transfer Units = Math
    3.094 = 3.094
  5. Calculate Height of Transfer Unit
    Height of Transfer Unit
    0.55 = 0.55

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