Scrubber

We install absorption columns (scrubbers) as they exploit the principle of absorption, an operation based on the transfer of a substance from the gaseous phase to the liquid phase. We mainly install them on gaseous effluents containing ammonia, various basic compounds, various acid compounds, various organic compounds and odours. We insert an abatement solvent into them, generally using substances that are low-hazard, inexpensive and have a strong liquid-phase interaction with the pollutant molecule. Since adsorption is understood as the removal of a pollutant, the destination of that pollutant once absorbed must be clear. The choice that allows the highest absorption efficiency, with the same solvent consumption and number of stages, is the countercurrent system, realised in scrubbers in which the liquid enters from above and descends in countercurrent contact with the gas fed from below. We usually use columns filled with materials with a large specific surface area, which are completely wetted. 

An incorrectly dimensioned Diameter/Height ratio drastically reduces abatement yields. Specifically, the motion of gas through the filling is normally turbulent and the pressure drop varies as a function of the square of the flow rate; moving from the flow of gas in the dry column to the flow of gas in the wet column, the pressure drop increases as the flow rate of the liquid fed increases. As the velocity of the gas increases, the amount of liquid retained by the filling increases, until the pressure drop assumes a much more rapid increase, due to the fact that the gas must support and pass through substantial levels of liquid. This point is known as the flooding point, as in this regime the equipment is completely unbalanced and liquid entrainment and gas by-passes occur, reducing the absorption efficiency. An important characteristic of the filling is its wettability, i.e. the minimum amount of liquid to be fed to the column to ensure a liquid film over the entire filling. Our experience in the operation and management of the process and the appropriate sizing of the column can avoid this phenomenon.