SEPARATION OF DIOXINS FURANES AND HEAVY-M ETALS WITH ZEOLITES

For cleaning flue gases from waste incineration plants, it is essentia l to apply enhanced measures for curbing pollutant concentrations, spe cifically with respect to mercury and its compounds as well as PCDD/PC DF, in order to meet statutory environmental standards. Adsorption pro cesses based on carbonaceous adsorbents are excellently suited for rem oving such pollutants since they are able to collect those substances from the offgas stream at high selectivity in spite of their low conce ntration. Contrary to other adsorbents of similar properties, zeolites boast the advantage of offering greater safety in operation. This mea ns that the safety equipment normally required, extinguishing faciliti es, measuring and control devices etc. can be omitted. There is no sel f-ignition hazard. Low-cost natural zeolites are especially appropriat e for application in circulating fluidized bed (CFB) reactors and entr ained-flow adsorbers. The MEDISORBON process uses a synthetic zeolite type which can be regenerated for reuse. The relatively high costs of the synthetic material compared with carbonaceous adsorbents can be co mpensated by savings in current operating costs, long service life of the adsorbent, minimum plant maintenance and low capital costs for equ ipment.