半合成与原位晶化催化裂化催化剂孔结构的研究

STUDY ON PORE STRUCTURE OF SEMI-SYNTHETIC AND IN-SITU CRYSTALLIZATION FCC CATALYSTS

对中国石油兰州石化分公司催化剂厂分别采用半合成工艺和原位晶化工艺制备的两种催化裂化催化剂(编号分别为LDO-75、LB-5)进行高温水热处理(编号为LDO-75-T、LB-5-T),考察两种催化剂高温水热处理前后的孔结构及水热稳定性。结果表明:LDO-75的孔体积和比表面积分别为0.27 cm 3 g和214.1 m 2 g,LB-5的孔体积和比表面积分别为0.35 cm 3 g和307.3 m 2 g,明显高于LDO-75;LDO-75和LB-5的最可几孔径分别为3.8 nm和6.3 nm;LDO-75和LB-5中的Y分子筛结晶度相近,但LB-5微孔比表面积达到216.0 m 2 g,明显高于LDO-75;水热处理后,LDO-75和LB-5的微孔比表面积保留率分别为44.4%和25.1%,说明LB-5存在不稳定的微孔结构;经水热处理后,LDO-75-T中孔径约3.8 nm的孔增加,而LB-5-T中孔径约6.3 nm的孔减少、孔径10~50 nm的孔增加。

Two catalytic cracking catalysts(numbered LDO-75,LB-5)prepared by semi-synthesis process and in-situ crystallization process were respectively subjected to high temperature hydrothermal treatment(numbered LDO-75-T,LB-5-T).The pore structures and hydrothermal stabilities of the two catalysts before and after high temperature hydrothermal treatment were investigated.The results showed that the pore volume and specific surface area of LB-5 were 0.35 cm 3 g and 307.3 m 2 g,respectively,higher than those of LDO-75 with 0.27 cm 3 g and 214.1 m 2 g.The most probable pore size of LDO-75 and LB-5 were 3.8 nm and 6.3 nm,respectively.Although the crystallinity of Y zeolite in LB-5 catalyst was similar to LDO-75 catalyst,the microporous specific surface area of LB-5 was 216.0 m 2 g,which was significantly higher than LDO-75.The microporous surface area retention rates of LDO-75 and LB-5 were 44.4%and 25.1%,respectively,after hydrothermal treatment,which indicated that LB-5 had unstable microporous structure.After hydrothermal treatment,the pore volume around 3.8 nm pore diameter of LDO-75-T increased,the pore volume around 6.3 nm of LB-5-T decreased,while that in range of 10—50 nm diameters increased.