湿式烟气脱硫中石灰石反应活性

在分析选自国内不同地区天然石灰石化学组成的基础上,对具有不同CaCO₃含量的石灰石进行了孔结构表征,并采用硫酸滴定法和气液吸收法,考察了石灰石的脱硫反应活性.结果表明,石灰石的比表面都在1.8m²/g左右.投加硫酸溶液到石灰石浆液后,浆液pH迅速下降到最低值,随后回升.随着石灰石CaCO₃含量提高或粒径减小,pH回升速率增大.石灰石CaCO₃含量愈高或粒径愈小,气液吸收反应器出口检测到SO₂之前所经历的反应时间愈长,出口SO₂浓度上升愈快.硫酸滴定法与气液吸收法测得的石灰石反应活性具有相同的规律.与颗粒比表面相比,CaCO₃含量对脱硫反应活性的影响更大.当粒径较大时(<300～360目),粒径对石灰石脱硫反应活性的影响较大,反之较小.

Reactivity of the Limestone in Wet Flue Gas Desulfurization

On the basis of the analysis of chemical components of the natural limestones from different deposits in China, the pore structures of the typical limestones, with the different CaCO3 content, were examined. The reactivity of the limestones was investigated by sulfuric acid titration and gas-liquid absorption methods. The research results showed that the specific surface area of the natural limestones studied in this work was about 1.8m^2/g. It was seen that the pH of the limestone slurry rapidly decreased and then back up when the sulfuric acid was added. The higher the CaCO3 content was, or the smaller the particle size was, the larger the pH back-up rate was, and similarly the faster the SO2 concentration of the reactor outlet increased. The Reactivity of the limestone obtained by the sulfuric acid titration had the same features as that obtained by the gas liquid absorption. Compared with the specific surface area, the CaCO3 content had more effect on the reactivity of the limestones. The particle size of the limestones had a significant effect on the reactivity when the particle size was relatively large, that is less than 300-360 mesh, vice versa.