Pt/CeL重整催化剂的制备及其石脑油芳构化性能

为克服常规氧化铝重整催化剂氯离子流失及其对设备的腐蚀等问题,通过离子交换法制备了Ce~(3+)改性的L分子筛,采用浸渍法制备了Pt/CeL重整催化剂;用XRD、N_2吸附-脱附、NH_3-TPD和Py-FTIR等手段对载体和催化剂进行了表征,并以硫含量为0.50μg/mL的工业精制石脑油为原料,在固定床微型反应装置上评价了Pt/CeL催化剂的重整芳构化性能。结果表明,Ce~(3+)离子交换可提高载体的酸量和酸强度,而不会破坏L分子筛的骨架结构;Ce~(3+)改性后的Pt/CeL催化剂其重整芳构化性能明显提高,活性与选择性达到氧化铝型商业重整催化剂的水平,说明适当的酸性对重整催化剂芳构化反应有显著的促进作用。

Preparation of Pt/CeL reforming catalyst and its performance in the aromatization of naphtha

To solve the problems of chlorine loss and equipment corrosion caused by the conventional alumina-type reforming catalyst, zeolite L was modified with Ce³⁺ by ion exchange method and with Ce³⁺-modified L (CeL) as the support, the Pt/CeL reforming catalyst without any chlorine was prepared by impregnation method. The CeL support and Pt/CeL catalyst were characterized by XRD, N₂ adsorption-desorption, NH₃-TPD and Py-FTIR; the catalytic performance of Pt/CeL in aromatization was investigated in a continuous-flow fixed-bed micro-reactor, with an industrial hydrofining naphtha containing 0.50 μg/mL sulfur as the feedstock. The results indicate that the modification with Ce³⁺ by ion exchange has little influence on framework structure of zeolite L; however, it can raise the acid content and acid strength of the CeL support and then remarkably enhance the performance of the Pt/CeL reforming catalyst in aromatization. The activity and selectivity of the Pt/CeL catalyst are comparable to those of the commercial alumina-type reforming catalysts, suggesting that proper acidity can facilitate the aromatization reaction.