Paper details

Title:

Sewage Sludge Fast Pyrolysis in a Conical Spouted Bed Reactor

Author(s):

Alvarez, J., Lopez, G., Amutio, M., Artetxe, M., Erkiaga, A., Barbarias, I., Arregi, A., Olazar, M.

Document(s):

Abstract:

The fast pyrolysis of sewage sludge has been performed in the 450­600 ºC range in a continuous pyrolysis bench­scale plant equipped with a conical spouted bed reactor (CSBR). The effect of temperature on the pyrolysis yields and main chemical products of the bio­oil has been determined. The liquid yield peaks (48 wt. %) at 500 ºC and the amount of bio­oil above this temperature decreases due to secondary cracking reactions undegone by the pyrolysis vapours. The char yield is very high in the whole range of temperature studied (42­55 wt. %) due to the high ash content of the feedstock (40 wt. % on a dry basis). The gaseous fraction is between 3­12 wt. % and its yield increases with temperature due to the severity of cracking reactions. These results evidence the suitability of the CSBR for maximizing the liquid yield because it allows reducing the gas residence time and improving the gas­particle contact by fast removal of the char from the reaction environment. Consequently, secondary reactions are minimized and the amount of bio­oil obtained is high. The bio­oil has been analyzed by GC­MS and is made up of a mixture of complex organic compounds, including oxygenated and nitroganated compounds as well as a few hydrocarbons. The organic hydrocarbons containing nitrogen such as pyridines, pyrazines nitriles or amides are derived from proteins and nucleic acids present in dead microorganisms, whereas oxygenated hydrocarbons, such as phenols, ketones, alcohols and saccharides come from undigested material (cellulose and fecal matter).

Keywords:

biomass, fast pyrolysis, pyrolysis oil, sewage sludge

Topic:

Biomass Conversion Technologies for Intermediates, Liquid and Gaseous Fuels, Chemicals and Materials

Subtopic:

Pyrolysis and other biomass liquefaction technologies

Event:

22nd European Biomass Conference and Exhibition

Session:

3CO.14.3

Pages:

939 - 945

ISBN:

978-88-89407-52-3

Paper DOI:

10.5071/22ndEUBCE2014-3CO.14.3

Price:

FREE