Effects of Calcium Peroxide on Desulfurization and Combustion Efficiency during Coal Combustion

Abstract

When applied for desulfurization in the coal combustion process, traditional sulfur sorbents have very low sorbent utilization and normally have a negative effect on combustion efficiency. A new type of sulfur sorbent, calcium peroxide (CaO2), synthesized from natural limestone, is proposed and its effects on desulfurization and combustion efficiency are investigated in this paper. The first series of experiments were carried out in a drop tube furnace (DTF). The results showed that CaO2 captured more sulfur than limestone and improved the burnout behavior of coal. To investigate the sulfur removal efficiency of CaO2, the second experiment was carried out in a fixed bed. The results indicated that the sulfur capture capability of CaO2 definitely exceeds that of limestone no matter whether in a low or high temperature range. Moreover, the combustion behavior of coal with and without CaO2 addition was investigated using thermogravity (TG) and differential scanning calorimetric (DSC) analysis. An increase of combustion reactivity and exothermic behavior were determined during the coal combustion process. Furthermore, the possible accelerative mechanism of CaO2 on desulfurization and combustion efficiency is proposed based on further experimental evidence.