Distribution of Heavy Metals in the Distilling Fractions from Sewage Sludge Pyrolysis Oil

Abstract

Pyrolysis is one of promising disposal outlets for sewage sludge. The behavior of heavy metal ions is always paid attended to in the solid sludge and char during sludge pyrolysis process. Here, the distribution of metals in the pyrolysis liquid and its distilling products was analyzed. It was found that the high content of Al and Ca do not appear in the pyrolysis oil and only about 10% of total metals come into the liquid during sludge pyrolysis. Through comparing of the metal content of pyrolysis oil and its process products, it is inferred that distillation is a feasible method for desalt from pyrolysis oil. During distillation, most metals are enriched in the residue. The pyrolysis oil and its products must be desalted deeply if they want to use in engine.