Separation of dust, halogen and PCDD/F in a compact wet scrubber

U p-to-date exhaust gas cleaning systems of waste incineration plants are h ighly effective, yet expensive in terms of equipment and other expenses. Ai ming at a simpler, but nevertheless effective system, a compact wet scrubbe r was developed that consists of several venturi scrubbers working in self- priming mode. The venturi scrubbers are located at the bottom of a multista ge packed tower. This compact apparatus incorporates several of the steps o f a conventional exhaust gas cleaning process, such as dust separation, que nch, acid and basic wet cleaning. Therefore, investment and running costs f or the gas cleaning process are reduced without any loss of separation effi ciency. The design concept and important experimental results of the compac t scrubber are reported. The scrubber has been employed at a hazardous wast e incineration plant in order to test its applicability under real conditio ns. The experiments were used to identify benefits and drawbacks of the scr ubber, and to improve the scrubber design concept. It is shown that the dev eloped scrubber is highly effective in separating fine dust particles and i norganic-gaseous pollutants (HCl, HF, SO2). Additionally, the concentration of polychlorinated dioxins and furans (PCDD/F) is significantly reduced in the off-gas of the scrubber. These compounds are adsorbed into plastic pac king materials.