Experimental Investigation and Modeling of G asification of Sewage Sludge in the Circulating Fluidized Bed

摘要

Experiments of sewage sludge gasification were performed in a circulating fluidized bed of pilot plant scale. For the examination of the influence of the air ratio, gasification temperature, feeding height and fluidization velocity several screening tests were conducted. To get more insight into the process, axial profiles of the gas composition were measured. As the most influencing factor for the heating value of the gasification gas the air ratio was found. Additionally, a low feeding height is recommended for good gas quality. In a second step a model of the CFB gasifier was developed. The fluid dynamics of a CFB were included as well as the complete reaction network of gasification. With the measured axial profiles of gas composition during pyrolysis, and gasification with air and a CO_2/N_2-mixture the kinetic rate expressions for to sewage sludge gasification were determined.