Effect of Phosphorus on Desulfurization of Limestone during Sewage Sludge Combustion

Abstract

Experiments of desulfurization of limestone during sewage sludge combustion with different phosphorus contents were conducted in a 15 kW circulating fluidized bed test rig to investigate the effect of phosphorus on desulfurization. Chemical thermodynamic analysis was performed to compare with the experimental results. Chemical thermodynamic analysis indicates that relatively high content of phosphorus in sewage sludge will affect desulfurization because calcium will first react with phosphorus and then the rest is available for reaction with sulfur, which agrees well with the experimental results. The experimental results also show that relatively high content of phosphorus in sewage sludge affects self-desulfurization of calcium in sewage sludge and desulfurization of limestone. The effect of phosphorus on desulfurization must be taken into account during sewage sludge combustion.