Coalescing

Nuclear coalescing - or ‘demisting' - involves the removal of a liquid aerosol from a gas stream, as opposed to a liquid droplet suspension from a second, immiscible liquid stream. The effective removal of liquid aerosol in filtered gas streams is important because the presence of liquids in gas filtration can have potentially damaging effects on the performance of gas filters. Increased pressure loss, reduction in filtration efficiency, or even complete blocking of the filter element if the pressure in the system is insufficient to clear the capture water from the filter medium, can all be deleterious to effective operation.

The mechanisms used in the removal, collection and extraction of water droplets from a gas stream do not follow classical filtration processes. While the simple removal of solid particles from a gas stream sees them exhibit and experience a series of well understood mechanical and physical effects, when coalescing or demisting water droplets or mist from a gas stream prior to that stream's actual filtration, the water particles are first intercepted by a separation medium, which then gathers them together into larger droplets. Those droplets then become large enough to overcome the surface tension attaching them to filter medium fibres, before they are either expelled from the filter pores or become heavy enough to drain down through the medium to be captured and finally discharged from the system.

As unrivalled experts in the field of engineered solutions to nuclear filtration applications, Porvair Filtration Group can offer liquid removal systems for gas streams to optimise eventual particulate removal.