Wetted wall columns have been designed to study the absorption of air oxygen into deoxygenated water prepared
with nitrogen. Absorption enthalpy and solubility are low in this system, and saturating the inlet air with water, will eliminate the effect of auto evaporation; absorption occurs isothermally in these conditions. The system components are assembled on a framework of stainless steel with castors. The wetted wall column consists of a vertical tube of glass where the entering liquid is distributed uniformly onto the inner surface. The absorbing liquid is stored in a tank and is pumped to the top of a deoxygenation column available aside the absorption column; injecting nitrogen into the column bottom will deoxygenate the water. Then the deoxygenated water will be pumped to the top of the absorption column after crossing a variable area flowmeter. The air is pumped by a compressor to the bottom of the absorption column through a variable area flowmeter and it goes up in the column transferring oxygen to the water. The concentration of dissolved oxygen and the inlet and outlet temperatures of the liquid are measured by two sensors. The water coming out of the column is collected into the feeding tank so that it can be recycled to the deoxygenation column by a pump.
TRAINING PROGRAM
This unit enables to deepen the following issues:
• Calculation of mass transfer coefficient in liquid film
• How flow rates of water and air can affect the mass transfer coefficient
TECHNICAL SPECIFICATIONS:
• Framework of AISI 304 stainless steel with castors
• Tank of AISI 304 stainless steel with capacity of 45 litres
• Wetted wall column of borosilicate glass, H = 900 mm, DN 40 (inside diameter = 34 mm)
• Deoxygenation column of transparent Plexiglas, H = 1600 mm, DN25
• Variable area flowmeter for water with glass tube and range of 1.9-19 l/h
• Variable area flowmeter for air with glass tube and range of 30-300 l/h
• Pump for deoxygenator
• Pump for absorption column
• Air compressor
• 2 board-type industrial oxymeters, 0-20 mg/l or 0-200%, resolution of mg/l or 0.1% SAT
• 2 industrial measuring sensors of dissolved oxygen
• Switchboard IP55, complying with EC conformity mark, including plant synoptic and ELCB
• Emergency button
• Power supply: 230 Vac 50 Hz single-phase – 0,5 kVA (Other voltage and frequency on request)
