Book/Report

FZJ-2019-00148

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Untersuchungen zur Verfahrenstechnik der Klärschlammpyrolyse und der Verwendbarkeit des Pyrolysekokses

Rumphorst, M. (Corresponding author)FZJ*

1994
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/21130

Report No.: Juel-2999

Abstract: Due to its pollutant load, more than 50 million m$^{3}$ of sewage sludge per year represents an ever increasing problem for waste management. Pyrolysis presents itself as a possible step in sewage treatment, since in addition to achieving a volume reduction of the residue it also opens up the possibility of producing reusable materials. The present work explores more closely process engineering influences in the pyrolysis of sewage sludge, paying particular attention to the properties and application possibilities of the pyrolytic coke produced. Excess sludge from a municipal sewage works was selected for the pyrolysis experiments. It was dried in air, comminuted and homogenized. An externally heated shaft reactor of quartz glass was selected for the pyrolysis experiments. The pyrolysis temperature was varied from 500 to 900°C. Approx. 100 - 200 g of sludge was let into the cold and also into the hot reactor. In further experiments, only mechanically dehydrated, not dried sludge was pyrolysed. The experiments with dried sludge yielded approx. 40 - 50 wt% coke, 40 - 10 % condensate and 10 - 30 % gas as a function of temperature. The major constituents of the pyrolytic coke were determined after proximate analysis. PAHs were no longer detectable in the coke above a pyrolysis temperature of approx. 700°C, while the PCBs had dropped to 1/10 to 1/20 of the value in the sewage sludge. Except for mercury and cadmium, the heavy metals were quantitatively recovered in the coke. In order to describe the adsorption capacity of the coke, its specific surface accor ing to BET and its iodine value were determined. BET values of between 20 and 90 m$^{2}$/g were measured and the iodine values were approximately twice as high. In order to establish possible areas of application for pyrolytic coke, the adsorption of benzene, phenanthrene and dibenzofuran from the gas phase was studied incomparison to lignite coke in a laboratory facility. For both types of coke, loads were determined in approximately the same proportion as their specific surfaces. Theadsorption of phenanthrene and dibenzofuran was similar for both adsorbents. The pyrolytic coke was loaded with about 12 mg/g of these pollutants. Finally, the possible reuse of pyrolytic coke in a sewage works was investigated. To this end, pyrolytic coke and lignite coke dust respectively were fed into two laboratoryscalesewage plants. A similarly great improvement in nitrification and also in mechanical dewaterability was found for both types of coke. The cokes apparently served as a growth surface for microorganisms.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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