用浸渍法制备了稀土改性HZSM-5分子筛催化剂(简称RE/HZSM-5),研究了RE/HZSM-5对混合C4烃(包括C4烷烃和C4烯烃)裂解活性及低碳烯烃收率的影响.结果表明,RE改性后HZSM-5分子筛催化剂的裂解活性明显增加,轻稀土改性HZSM-5分子筛比重稀土改性的表现出更好的增产低碳烯烃裂解性能.在0.1MPa,重时空速(WHSV)=1.2×104 mL/h*g-1条件下,轻稀土La、Pr、Nd、Sm、Gd改性HZSM-5分子筛催化剂上混合C4烃催化裂解产物中乙烯和丙烯总收率在625℃时达到最高,分别为54.66%、54.32%、53.32%、54.15%和54.06%,比相同条件下未改性的HZSM-5高3%~4%.重稀土中只有Yb/HZSM-5表现出较好的裂解活性,裂解产物中乙烯和丙烯总收率在600℃时达到最高,为54.80%.用红外光谱(FT-IR),氨程序升温脱附(NH3-TPD)和吡啶吸附红外光谱法(Py-IR)法对RE/HZSM-5分子筛进行了表征,结果表明催化剂的总酸量、B酸与L酸的比值与催化活性之间存在密切关系.
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