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Gas Absorption Column

The Armfield Gas Absorption Column has been designed to demonstrate the principles of gas absorption, and to provide practical training in the operation of a gas absorption plant.

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UOP7MkII Gas Absorption Column – Issue 1

The Armfield Gas Absorption Column has been designed to demonstrate the principles of gas absorption and to provide practical training in the operation of gas absorption plant.

Ordering Specification

  • An apparatus for teaching the principles of the absorption of gas into liquid, using a packed column
  • Column working length is 1.4m x 80mm diameter, split into two sections
  • Two electronic pressure sensors measure the pressure drop across each half of the column
  • An electronically controlled submersible pump provides a liquid flow of 1-10 l/min
  • 60l feed tank
  • Water flow can be used in either recycle or one-pass operation
  • Column supplied with 10mm x 10mm Raschig rings as packing material, total volume 7l. Other sizes can be used
  • Centrifugal fan provides air flow up to 160 l/min
  • Two electronic temperature sensors measure the air and liquid temperatures
  • Electronic measurement of CO2 concentration in the air streams, measurements can be taken at the column inlet and outlet
  • Sensor values displayed on an alpha-numeric display on the control console
  • Data logging as standard (requires PC, not supplied)

Demonstration Capabilities

  • Study of basic priciples of the absorption of a gas into a liquid using a packed column
  • Determination of loading and flooding points
  • Study of hydrodynamic characteristics of a packed column
  • Demonstration of physical and chemical absorption
  • Investigation of the effectiveness of CO2 absorption in pure water and in an aqueous solution
  • Demonstration of gas desorption
  • Determination of the mass transfer coefficient


In the process of gas absorption, a mixture of gases is contacted with a liquid, for the purpose of dissolving one or more components of the gas and to provide a solution of them into the liquid.

In UOP7MkII, a gas phase consisting of CO2 and air is introduced into the bottom of the packed column. Adjustment of their flow ratio is obtained by manual valves. A sample of the gas mixture is sent to a CO2 concentration sensor located inside the electric console, and readings of flows and CO2 percentage concentration are seen on the display.

For the liquid phase, water (or a solution of sodium hydroxide) is pumped to the top of the column where it falls through the packing material. The contact of the two phases is in counter-current operation and enhances the mixing and diffusion of CO2 in the liquid phase at the conditions of room temperature and atmospheric pressure.

The outlet gas leaves the system from the top of the column. A sample of the outlet gas mixture is also taken and sent to the CO2 sensor located inside the console. Reading of CO2 concentration is shown on the console's display.

The outlet liquid leaves the system from the bottom of the column and returns to the water tank. Samples of the liquid phase entering and exiting the system can easily be taken for further analysis.

Desorption of the CO2 absorbed in the water line is obtained by aeration of the 'charged' liquid.


Unit Characteristics

The packed absorption column is made of clear acrylic and is installed vertically on a mild steel floor-standing framework. The column is filled with 10mm x 10mm of glass Raschig rings, which are representative of random packing used in gas absorption on an industrial-scale. Liquid is stored in a feed tank and a variable speed submersible pump is used to pump the liquid into the column. An electronic flow meter sensor is installed in the water line to provide accurate measurement of the liquid flow entering the column.

The gas to be absorbed is carbon dioxide (CO2), and would be taken from a pressure cylinder (not supplied). Gas regulator, control valve and electronic flow meter are used to regulate gas flow. A centrifugal fan provides air flow to the column. The air line also includes a gate valve for flow control and an electronic flow meter.

Pressure tappings at the base, centre and top of the column are provided to enable indication of pressure drops in the column using electronic pressure sensors.

Liquid and gas temperature readings are obtained by thermistors in the liquid tank and the inlet gas line.


Electrical supply:
UOP7-MkII-A: 220-240V / 1ph / 50Hz / 2 amp
UOP7-MkII-B: 115V / 1ph / 60Hz / 4 amp
UOP7-MkII-G: 220-240V / 1ph / 60Hz / 2A

Water supply:
5 l/min at 2 bar

CO2 supply:
20 l/min at 1 bar

Computer: A Windows PC (not supplied) running Windows 98 or later, with USB port is required if running the data logging software

Overall Dimensions

Height: 2.876 m (1.781m disassembled)
Width: 1.017m
Depth: 0.667m
Net weight: 100kg (dry, unpacked)

Shipping Specification

Gross weight: 200kg
Volume: 2.2m3