Behavior of nitrogen and sulfur in the char produced from bio-dried sludge

Abstract

In order to evaluate nitrogen and sulfur behavior during carbonization, carbonization experiment with bio-dried sludge was conducted in a horizontal lab-scale reactor and rotary kiln. Bio-dried sludge dried by using fermentation was used as the carbonization material. Carbonization temperature was changed from 573 to 1173K, and the effect of steam introduction on the elements behavior during the carbonization process was revealed. Nitrogen in the bio-dried sludge decomposed linearly with rising treatment temperature, and more than 90% of nitrogen decomposed at the 1173 K temperature. Sulfur in bio-dried sludge decreased slowly with increasing treatment temperature, but the decreasing ratio was insignificant against the carbonization temperature. Around 70 % of sulfur remained in the char after the carbonization at 1173 K. Sulfur behavior was changed when the steam was introduced during the carbonization. Sulfur content in the char was decreased significantly.