Influence of Phosphorus Compounds on Sulfur Releasing during Coal and Sewage Sludge coGasification

The volatilization of sulfur during cogasification process of sewage sludge with Shenfu coal was investigated. Influence mechanism of phosphorus compounds on sulfur releasing was discussed based on Xray diffraction (XRD) and thermodynamic calculation. The results show that aluminum phosphate from sewage sludge can react with anhydrite and then lead to the releasing of sulfur at low gasification temperature, especially between 900 ℃ and 1 200 ℃. Sulfur volatilization ratios of sludgecoal mixtures, which phosphorus mass fraction is 0.5% and 1.0%, are 19.2% and 35.5% higher than Shenfu coal respectively at 1 000 ℃. When temperature is higher than 1 300 ℃, most sulfur in mixtures volatilizes, and the influence of sewage sludge on sulfur volatilization ratio is not significant.