KOMBISORBON? PROCESS, A COMBINED ACTIVATED CARBON BASED ADSORBENT FOR REMOVAL OF ECO-TOXIC COMPONENTS LIKE DIOXINS OR MERCURY FROM FLUE GAS

摘要

Ever increasing demands are made on plant operators and plant engineers with respect to the conceptualrndesign of the off gas cleaning section in order to comply with the emission limits imposed by the legislation forrnthe off gas content of heavy metals and dioxins/furans as toxic components.rnThe process presented is a fixed bed process which constitutes a method for safe compliance with the emissionrnlimits and for retaining the toxic components which relies on non-inflammable mixtures of carbon-containingrnadsorbents and inorganic inert material.rnFor decades, activated carbon has been applied in fixed bed adsorbers. Activated carbon has by far the bestrncollection and adsorption properties of all adsorbents known hitherto and covers the widest range of application.rnTo overcome the problems which may occur in connection with the use of pure carbon adsorbents, fouling andrncorrosion as well as the hot spot hazard, the development of the KOMBISORBON fixed bed technology was pursued.rnThe process can be applied for reducing metallic mercury, for separating HgCl2 and other Hg compounds asrnwell as other heavy metals like cadmium and for the safe separation of all toxic organic compounds such as chlorinatedrnand bromated hydrocarbons like dioxins, furans, PCB′s, hexachlorbenzene or polyaromatic types.rnThe KOMBISORBON-mixture is suitable for use in low-cost-fixed-bed adsorbers without the need for safetyrnprecautions such as CO measurement or intertization. Depending an application and waste gas amount differentrnstandard apparatus are available which can handle up to 60,000 acfm (100,000 m3/h) in one vessel. According torngas specification, the adsorbers can be produced out of normal steel, stainless steel or fibre reinforced plasticrn(FRP).rnBy varying the carbon/inert material mixing ratio and modifying the activated carbon, e. g. through impregnation,rnthe adsorbent can be adapted to a great variety of uses. In this way, optimum solutions can be developedrnfor the specific application.rnTypical applications are for sewage sludge or hazardous waste incineration plants. All erected plants so farrnare running properly. For example, in the first commercial-scale KOMBISORBONa unit, installed in a sewagernsludge incineration plant in 1994, the first filling has been operated for four years and still achieved more thanrn90% removal efficiency for Hg when replaced.