摘要
以超细氧化硅为载体,高硅铝比的ZSM-5分子筛为活性组分,挤条制成催化剂,用氧化钙和氧化镧的前驱体化合物改性,分别在800℃焙烧和600℃水蒸汽的条件下进行处理,在500℃、0.1MPa、水与碳四质量比0.2和碳四空速3 h^(-1)的条件下,对催化剂性能进行评价。对成型、改性、水热处理和再生后的催化剂采用BET、NH_3-TPD和Py-IR方法进行表征。结果表明,催化剂长时间在800℃焙烧和600℃水蒸汽条件下处理后活性降低,催化剂活性与表面L酸量和B酸量变化有关。
The catalyst for catalytic cracking of C4 alkenes to propylene was prepared using ultra-fine silicon oxide as the carrier and ZSM-5 molecular sieve with high SiO2/Al2O3 molar ratio as the active component. The precursors of CaO and La2O3 were used to adjust the acidic properties of the catalyst. The catalysts co-modified by CaO and La2O3 were pretreated at 800 ℃ under the protection of inert gas for 48 h or at 600℃ with water vapor for 24 h. The properties of the catalysts were investigated under the the reaction condition as follows: 500℃,0. 1 MPa,w(H2O): w(C4= ) =0. 2, C4 space velocity 3 h-1 ,and continuous operation for 25 days. The as-prepared catalysts were characterized by BET, NH3-TPD and Py-IR. The results showed that the activity of the catalysts were decreased after long time treatment at 800 ℃ or 600℃ with water vapor. The characterization results indicated that the catalytic activity of the catalysts was related to the contents of Lewis acid and Bronsted acid on its surface.
出处
《工业催化》
CAS
2011年第6期54-57,共4页
Industrial Catalysis