温度对石灰石还原脱硫特性的影响

Effect of Temperature on the Sulfidation of Limestone at Reducing Atmosphere

在Thenmx500型加压热重分析仪上进行了还原条件下石灰石的直接脱硫实验，主要研究了温度（700-950℃）对石灰石与H2S反应的影响．分别采用扫描电镜（SEM）以及氮吸附等实验手段对反应样品的颗粒表观结构和BET孔隙特性进行了分析．实验发现，温度对脱硫反应影响较大，随着温度的升高，初始反应速率增加，但不一定能得到高的最终转化率．CO2气体的存在不利于反应的进行．通过热重实验以及SEM分析，发现产物层CaS的烧结使得CaCO3在高温下脱硫效果变差．

Sulfidation experiments with limestone were performed in a pressurized thermogravimetric analyzer （Thermax 500） under noncalcining conditions. The effects of reaction temperature （700-950 ℃ ） on sorbent conversions were analyzed. Morphological studies with scanning electron microscope （SEM） were carried out to obtain the pictures of solid surface to illustrate the changes in particle structure. Nitrogen adsorption measurements were used to determine the physical properties of such samples as surface area and pore volume. Experimental results show that temperature greatly affects the reaction between CaCO3 and H2S, and the initial reaction rate increases with temperature; however, it is not necessary to obtain a high final conversion at high temperatures. Poor conversion of the sample upon reaction with H2 S is caused by sintering of CaS product layer, which can be seen from SEM photographs. At higher temperature, the sintering of sample is more serious. In addition, CO2 also accelerates the sintering of CaS, resulting in a decrease in sulfidation rate.