The oxidation of CaS to a CaSO₄ oxygen carrier suffers SO₂ release. To capture SO₂ released, an amount of CaO particles was mixed with CaS particles. Isothermal kinetics of the CaS–CaO oxidation reaction has been conducted in a thermogravimetric reactor combined with a Frourier transform infrared spectroscopy (FTIR) analyzer. The effects of the reaction temperature, O₂ concentration, and molar ratio of CaO/CaS on CaSO₄ generation and SO₂ emission were investigated. The chemical compositions, morphology structures, and element distributions on the surfaces of solid residuals were characterized by FTIR and scanning electron microscopy–energy-dispersive X-ray spectroscopy instruments. The results show that the oxidation products of CaS species are mainly composed of CaSO₄. A small amount of SO₂ is released from CaS oxidation, causing losses of the oxygen carrying capacity of a CaSO₄-based oxygen carrier. Using a CaO additive in the CaS oxidation process reduces SO₂ liberation, improves the CaSO₄ selective yield, but results in an increase in remaining CaS species in solid residues. There is a general positive correlation between the remaining percentage of CaS species and the SO₂ selective yield. The SO₂ liberation varies with the reaction temperature, O₂ concentration, and CaO/CaS molar ratio. At 900 °C, a CaO/CaS molar ratio of 1, and 5% O₂, SO₂ released from CaS oxidation is completely trapped by the CaO additive.

中文翻译：

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CaSO _4基氧气载体对化学环流燃烧的CaS–CaO氧化特性

CaS氧化为CaSO ₄氧载体会释放SO ₂。为了捕获释放的SO ₂，将一定量的CaO颗粒与CaS颗粒混合。CaS–CaO氧化反应的等温动力学已经在热重分析仪中与Frourier变换红外光谱（FTIR）分析仪结合使用。反应温度，O ₂浓度和CaO / CaS摩尔比对CaSO ₄生成和SO _2的影响排放进行了调查。固相残余物表面的化学成分，形态结构和元素分布通过FTIR和扫描电子显微镜–能量色散X射线光谱仪进行了表征。结果表明，CaS物种的氧化产物主要由CaSO ₄组成。CaS氧化释放出少量的SO ₂，导致基于CaSO ₄的氧载体的载氧能力下降。在CaS氧化过程中使用CaO添加剂可减少SO ₂释放，改善CaSO ₄选择性收率，但会导致固体残渣中残留的CaS种类增加。CaS物种的剩余百分比与SO ₂选择性产量之间通常存在正相关关系。SO ₂释放随反应温度，O ₂浓度和CaO / CaS摩尔比而变化。在900°C下，CaO / CaS摩尔比为1，5％的O ₂，从CaS氧化释放的SO ₂被CaO添加剂完全捕获。