脱硫剂微观结构对脱硫性能的影响

采用扫描电镜和压汞仪对3种贝壳和1种石灰石的微观结构及孔径分布进行了测量,采用热重分析方法对各种脱硫剂的脱硫性能进行了测试.比较发现,各种贝壳煅烧后的晶粒呈薄片状,晶粒之间孔径均大于0.2μm,比孔容较大;石灰石煅烧后晶粒呈颗粒状,晶粒之间孔径多数在0.01～0.16μm之间,比表面积很大,但比孔容较小.贝壳中直径大于0.2μm的气孔,允许气体扩散至颗粒内部,气孔表面同时参加脱硫反应,且反应过程中不易被反应产物所堵塞,脱硫反应进行较彻底,钙利用率较高.另外,在满足气体扩散的前提下,减小孔径尺寸,增加反应比表面积,将对脱硫反应有利.

The Effect of Microstructure on the Desulphurization of Absorbents

The microstructure and the pore size distribution of 3 kinds of shell and 1 kind of limestone were measured with electronic scanning microscope and pore master mercury porosimeter, and the desulphurization characteristics of above absorbents were studied with thermal-gravimetric analyzer. As a result, the grains of calcium from shell like tortuous flakes, with pore diameter above 0.2 micron and higher pore volume, while the grains from limestone like particles, with pore diameter between 0.01 to 0.16 micron and lower pore volume, but the surface area were very high. The bigger pore which was above 0.2 micron in shell had many advantages, such as fewer air-blocked pores, lower gas diffusing resistance, almost simultaneous and completed reaction. So, finally the calcium conversation ratio of the shell was greater than that of the limestone. On the other hand, while the gas diffusion was meted, it was effective for desulphurization to reduce the pore size and to increase the surface area.