煤焦油催化裂解过程钙-镁催化剂的抗积炭性能

Anti-Carbon Deposition Performance of Ca-Mg Catalyst in Coal Tar Catalytic Cracking Process

采用两段式固定床反应器进行了煤焦油Ca-Mg催化裂解的实验研究,通过X射线衍射(XRD)、扫描电镜(SEM)及比表面积测试(BET)等手段表征反应前后Ca-Mg催化剂的物化特性,考察了添加Fe2O3助剂对Ca-Mg催化剂抗失活性能的影响。结果表明:长时间裂解反应中积炭叠加导致Ca-Mg催化剂失活,当积炭率达到3%~5%时,出现焦油裂解率降低的拐点;Ca-Mg催化剂中Fe2O3的加入,因积炭与Fe2O3发生慢速固-固反应,明显延迟了Ca-Mg催化剂活性拐点的出现,从而提高了Ca-Mg催化剂的抗积炭性能。

A two-stage fixed-bed reactor was employed to investigate the catalytic cracking of coal-tar on calcium-magnesium catalysts surface.Physicochemical properties of the Ca-Mg catalyst before and after the reactions were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM)and specific surface area testing(BET).Effects of iron addition on the anti-deactivation activity of the Ca-Mg catalyst were discussed.Experimental results suggest that accumulation of carbonaceous deposits under long-time cracking reactions leads to the deactivation of Ca-Mg catalyst.When carbonaceous deposits ratio on the catalyst reaches 3%-5%,tar cracking activities will start to decrease.When Fe2O3 is added,the solid-solid reaction occurs between carbonaceous deposits and Fe2O3.This can postpone the inflection points of catalyst deactivity,and thus improve the capability of carbon deposition resistance of the Ca-Mg catalyst.