煤担载高分散铁镍催化剂在煤/重油加氢共炼中的活性研究

采用沉淀-空气氧化法制备煤担载型高分散铁基催化剂(Fe/C),并引入第二金属镍得到Fe-Ni/C催化剂。采用XRD,HRTEM,SEM-mapping等分析了催化剂的晶相组成、形貌特征及活性金属在煤上的分散状态,高压釜实验对比了两种催化剂在煤重油加氢共炼反应中的催化活性,分析了反应后固体残渣的微观形貌。结果表明,Fe/C催化剂的主要活性成分为α-FeOOH和γ-FeOOH,引入镍后则生成了混晶相Fe 0.67 Ni 0.33 OOH,Fe、Ni活性金属在载体煤表面分布均匀。两种催化剂作用下的干基无灰煤转化率均高于97%,但Fe-Ni/C催化剂作用下产物分散性更好。固体残渣的SEM照片对比表明Fe/C催化剂体系中生成了较多球形焦炭,而Fe-Ni/C催化剂较强的加氢作用能有效抑制共炼体系中裂解中间产物的缩合生焦,在得到较高煤转化率的同时能有效降低固体残渣的粒径。

STUDY OF ACTIVITY OF HIGH DISPERSED Fe-Ni CATALYST SUPPORTED ON COAL IN CO-PROCESSING OF COAL AND HEAVY OIL

The high dispersed Fe catalyst supported on coal (Fe/C) was synthesized with the deposition-air oxygenation method, and the nickel was then introduced to obtain the Fe-Ni/C catalyst. The crystal structures, micromorphologies, and dispersions of active metals on the surface of coal were analyzed by XRD, HRTEM, and SEM-mapping. Catalytic activities of synthesized catalysts in the co-processing of coal and heavy oil were conducted in an autoclave, and the micromorphologies of solid residues were compared. The experimental results showed that the major active components of Fe/C catalyst contained ɑ-FeOOH and γ-FeOOH, whereas there existed a mixed crystal phase of Fe0.67Ni0.33OOH in Fe-Ni/C catalyst; the uniform distribution of Fe and Ni element on the surface of supported coals was observed. The dry ash-free coal conversion was over 97% for both the catalysts, but the dispersions of the products with Fe-Ni/C catalyst seemed to be more preferable. The comparison of SEM of solid residues indicated that certain amount of globular cokes was formed in the reaction system on Fe/C catalyst, whereas the relative higher hydrogenation activity of Fe-Ni/C catalyst could be beneficial to suppress the condensation and coke formation of intermediates derived from thermal cracking, which resulted in high coal conversion and solid residues having relative smaller particle sizes.