钾基复合催化剂对高硫石油焦气化性能的影响

以高硫石油焦为研究对象，探讨了水蒸气气氛下不同钾基催化剂、铁基催化剂以及K-Fe、K-Ca复合催化剂对高硫石油焦气化性能的影响。在1023 K、0.1 MPa下，钾基催化剂中KOH催化活性最高，而铁基催化剂中FeSO₄催化活性最高；在KOH基础上添加铁基催化剂后其催化性能有所降低；在K-Ca复合催化剂中，5%KOH和3%CaO(质量分数)复配时，催化剂的催化性能最好，石油焦碳转化率达到最高值61.33%，继续增加CaO添加量，K-Ca复合催化剂的催化性能降低。采用BET和XRD对K-Ca复合催化剂的催化作用机理进行研究，发现CaO的造孔作用以及石油焦气化反应过程中生成的双金属碳酸盐K₂Ca(CO₃)₂共同促进了气化反应的进行。而在压力增大的条件下，由于K-Ca复合催化剂中双金属碳酸盐K₂Ca(CO₃)₂的晶型发生转变，导致其催化活性相比添加KOH催化剂时降低。

Effect of Potassium-Based Composite Catalyst on Steam Gasification Performance of High Sulfur Petroleum Coke

Effect of K, Fe, K-Fe and K-Ca based composite catalyst on the steam gasification of high sulfur petroleum coke (PC) was investigated with using a pressurized fixed-bed reactor at conditions of 1023 K and 0.1 MPa. Experimental results show that, among potassium-based and iron-based catalysts, KOH and FeSO₄ have the best catalytic activity and highest carbon conversion rate for PC samples, respectively. After adding iron-based catalysts in KOH catalyst, carbon conversion rate of PC sample decreases. K-Ca catalyst, composed mass fraction of 5% KOH and 3% CaO, exhibits the best catalytic activity and can improve carbon conversion to 61.33%. Catalytic mechanism of K-Ca catalyst was also studied with BET and XRD analyses. It is found that CaO in the K-pores can promote potassium compounds diffusion and contact with petroleum coke, and subsequently enhance the steam gasification reaction due to the formation of K-Ca bimetallic carbonate (K₂Ca(CO₃)₂) during the gasification process. Furthermore, at the experimental conditions, the crystalline formed of K₂Ca(CO₃)₂ can be changed from buetschliite to fairchildite, and thus reduce K-Ca composite catalyst activity compared with just adding KOH alone.