Using Reclaimed Water in Scrubbers With Fouling-Resistant Q-PAC
Fouling problems in scrubbers are very much site-specific. There is no reliable way to predict the useful life of packing when solids can form in a packed bed. The operating experience of a scrubber at one plant can’t necessarily be repeated at another even if the scrubbers are identical, because they’re treating different air streams using different make-up water supplies.
Q-PAC scrubber packing was designed for fouling resistance. It has a high void fraction and a low initial pressure drop, so it takes more accumulated solids to seriously obstruct it compared to other scrubber packings.
When researchers at the Technical University of Munich rigorously compared the fouling resistance of various tower packings under identical, controlled conditions, they found , unsurprisingly, that larger random packings are more resistant to fouling than smaller ones. However, the useful life of Q-PAC under fouling conditions was substantially longer than would have been predicted from its dimensions alone. See excerpts.
Those test results have been borne out by real-world experience. For example, at semiconductor plants in the United States, Q-PAC has been chosen because it helps the plants to conserve water. In order to reduce fresh water consumption, low-quality reclaimed water in used in some large scrubbers. The reclaimed water contains calcium, magnesium, silica, and other impurities that gradually foul the scrubber packing. However, by using Q-PAC, those scrubbers run 24/7 for more than a year without a shutdown for packing cleaning or replacement, even when using reclaimed water. Packings whose pressure drops increase faster would cause problems at semiconductor fabs that need to operate all year without a shutdown.
