Die Abscheidung von Partikeln aus Gasen in Faserfiltern

Particle collection by fibrous filters . Technically employed fibre filters can be classified according to their construction and application in two major groups: deep bed filters and fabric filters. Approaches to the calculation of the collection efficiency for both types of filters start from a clean nondusted filter layer. From this one examines only the initial state, which is especially critical, while the degree of collection as a rule becomes better with increasing dust accumulation. Various models are available for the calculation of the pressure drop. The initial pressure drop for deep bed filters can be calculated with the help of the resistance model. Especially important are those estimates, which for purification filters describe the pressure drop or the gas flow with increasing dust accumulation, because these equations can serve directly for the dimensioning of filter plants. Of courese, characteristic permeability values for filter fabric and dust layer must be determined beforehand. The possibilities and problems of these calculations, as well as open questions, will be discussed.     

Die Abscheidung von polychlorierten Dioxinen und Furanen aus Abgasen mit Aktivkoksverfahren

Removal of Polychlorinated Dioxins and Furans from Off-Gases by Activated Charcoal. Discussions on solid waste incineration are dominated by the formation and emission of polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF). The predominant part of these substances remains in the fly ash, and less than 20% is present in the off-gases. Very stringent emission limits have been stipulated during recent years in many countries. The adsorption of PCDD/PCDF on carbonaceous materials has proved to be a very effective technique for their removal. Experimental results relating to gas clean-up, adsorber types, and concepts for the integration in plants are described.     

Abscheidung von Feinstaub aus Gasen

Extraction of fine dust from gases. The main focus of interest and of problems in the area of particle extraction from gases has been shifting more and more towards fine dusts, i.e. dusts with considerable fractions below 10 ßm, sometimes far below 1 ßm. Solution of extraction problems in this range either requires new processes, of which there are not many, or, on use of conventional extractors, calls for modified engineering concepts and modes of operation. This survey first describes some typical sources of fine dusts and then considers various procedures for their extraction.