摘要
以超细SiO_2为载体、水热稳定性好的高硅铝比ZRP-5分子筛为活性组分,通过挤条成型制成ZRP-5/SiO_2催化剂,采用碱土金属氧化物对催化剂进行改性,考察催化剂的活性与表面酸性的关系。结果表明,B酸与催化剂的活性相关,经MgO,CaO,SrO改性后,催化剂的酸性和活性随Mg,Ca,Sr原子半径的增大而降低。采用MgO-CaO/ZRP-5/SiO_2催化剂,在500℃、0.1 MPa、水与碳四混合物质量比0.2、重时空速3 h^(-1)的条件下连续反应50天,反应产物组成稳定,碳四烯烃转化率大于65%,丙烯收率大于31%,乙烯收率大于6%,再生后催化剂可以恢复到新催化剂98%的水平。
Using ultra-fine silica as carrier and ZRP-5 molecular sieve with high Si/Al ratio and good hydrothermal stability as active component, catalysts for catalytic cracking of C4 alkenes to propylene and ethylene were prepared by extrusion. The relationship between the catalytic activities and the acidic properties of the catalysts were investigated by modifying the catalysts with alkaline earth oxides. Results showed that the catalytic activities and acidities of catalysts modified by MgO,CaO and SrO decreased with the increase of atomic radius of Mg, Ca and Sr. The catalyst modified by MgO-CaO was evaluated on a fixed-bed reactor under a reaction temperature of 500 ℃,a reaction pressure of 0. 1 MPa, a H2 O/mixed C4 mass ratio of 0.2, a WHSV of 3 h land a continuous operation of 50 d, the conversion of C4 alkenes was more than 65 %, the yields of propylene and ethylene were more than 31% and more than 6 %, respectively. The catalytic activity of the regenerated MgO-CaO/ZRP-5/SiO2 catalyst was about 98 % of that of the fresh catalyst.
出处
《石油炼制与化工》
CAS
CSCD
北大核心
2011年第3期42-46,共5页
Petroleum Processing and Petrochemicals
