循环流化床O2/CO2燃烧技术是最具前景的燃煤电站CO2捕集方法之一。与常规循环流化床相比，烟气再循环带来炉内CO2、SO2和H2O等组分的富集，使煤燃烧过程S迁移规律（如石灰石的脱硫机理、SO3的生成等）变化很大，而目前尚缺少相关研究，尤其S的气固两相迁移定量化研究。采用小型流化床进行石灰石在O2/CO2/H2O气氛下的脱硫试验，获得水蒸气对石灰石脱硫途径的影响机理；采用滴管炉模拟O2/CO2燃烧烟气中SO3生成的气相和气固异相反应实验，探明气氛、飞灰物理化学性质等参数对SO3生成的影响机理。在探明机理的基础上，进行多种燃料的循环流化床O2/CO2循环燃烧试验，通过气固流量和S组分的准确测量，获得S的气固两相迁移定量数据，建立S平衡方程。本项目对于掌握循环流化床O2/CO2燃烧过程中S的迁移机理及抑制硫氧化物的排放具有重要的理论价值和现实意义。

Oxy-fuel circulating fluidized bed combustion is one of the most promising carbon capture technologies for coal-fired power plant. Due to the enrichment of CO2/SO2/H2O in the flue gas, the sulfur transformation behaviors （such as limestone desulfurization mechanism,SO3 formation, etc.）during oxy-CFB combustion will deviate substantially from air-fired CFB. However,the related study especially the quantitative investigation on sulfur fate in the gas and solid phase during oxy-fuel CFB combustion has rarely been involved at present. In this project, limestone desulfurization experiment under O2/CO2/H2O atmosphere will be carried out in a bench scale fluidized bed combustor to obtain the influence of vapor on the limestone desulfurization behavior. The SO3 formation experiment by homogenous and heterogeneous reactions will be carried out on a drop tube furnace and the effects of atmosphere, fly ash physical and chemical property, etc. on the SO3 formation during oxy-fuel CFB combustion will be revealed.Based on the mechanism obtained from the bench experiments, an oxygen/flue gas recycle CFB combustion experiment burning varied fuels will be accomplished to study the sulfur transformation behavior in gas and solid phase quantitatively,also the sulfur balance data will be achieved through the accurate measurement of the gas-solid flow and composition. It is of great theoretical value and practical significance to investigate the sulfur transformation mechanism for controlling sulfur oxides emission during oxy-fuel CFB combustion process.