A ZSM-5-based Catalyst for Efficient Production of Light Olefins and Aromatics from Fluidized-bed Naphtha Catalytic Crac
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A ZSM-5-based Catalyst for Efficient Production of Light Olefins and Aromatics from Fluidized-bed Naphtha Catalytic Cracking Jinlong Wan Æ Yingxu Wei Æ Zhongmin Liu Æ Bing Li Æ Yue Qi Æ Mingzhi Li Æ Peng Xie Æ Shuanghe Meng Æ Yanli He Æ Fuxiang Chang
Received: 19 December 2007 / Accepted: 19 February 2008 / Published online: 6 March 2008 Ó Springer Science+Business Media, LLC 2008
Abstract A ZSM-5-based catalyst was prepared by spraydry method for fluidized-bed naphtha catalytic cracking. Multi-techniques, such as X-ray diffraction, scanning electron microscope, 27Al MAS NMR, and NH3–TPD, were employed for the investigation of ZSM-5 framework stability, framework dealumination, and catalyst acidity variation in hydrothermal treatment. Catalytic performances of fluidizedbed naphtha catalytic cracking at 630–680 °C indicated that light olefins and other value-added products could be more efficiently produced compared with the commercial process of thermal steam cracking. Long-term catalytic evaluation implied that naphtha catalytic cracking over the catalyst prepared with spray-dry method and hydrothermal treatment can be carried out at a variable reaction condition with a relatively high and stable light olefins yield. Keywords Naphtha catalytic cracking Fluidized-bed ZSM-5 Hydrothermal treatment Light olefins Aromatics
1 Introduction Light olefins, ethylene and propylene, have the backbone status in petrochemical industry and are mostly used to produce plastics, fibers, and other chemicals. The main J. Wan Y. Wei Z. Liu (&) B. Li Y. Qi M. Li P. Xie S. Meng Y. He F. Chang Applied Catalysis Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 110, Dalian 116023, P.R. China e-mail: [email protected] J. Wan Graduate School of Chinese Academy of Sciences, Beijing 100039, P.R. China
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commercial technique for light olefins production is steam cracking of naphtha which requires high reaction temperature (800–880 °C). Energy cost of pyrolysis sector counts for *70% of production cost in typical naphtha-based olefins plants [1]. Though some innovative technology has been developed in term of energy efficiency, it is still the first energy-consuming process in petrochemical industry. Under the typical steam-cracking condition (820 °C, H2O/ naphtha = 0.7), about 30% of ethylene and 15% of propylene can be obtained. To improve the yield of light olefins and optimize the economical efficiency, the application of catalytic cracking process could be an option. Strong and increasing demand for propylene and the nonselectivity character of steam cracking has also driven the development of catalytic olefins technology. Several types of catalysts for naphtha cracking have been used in naphtha steam cracking and an enhanced olefin yield was obtained [2–5], but still no commercial application has been reported until now. Some of the reported catalysts worked at the temperature range of 750–780 °C, lower than the commercial process by about 50–100 °C. The most successful one is K
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