Hydroisomerization of n-dodecane on ZSM-48 with acid distribution modulation for high diffusion performance

作者：Wei Zhang, Jiangnan Xiang, Yuting Wang, Yuting Wang, Mengxi Ma, Yan Wang, Yan Wang, Bo Qin, Weijiong Dai, Binbin Fan, Jiajun Zheng, Ruifeng Li · 发表于：Fuel Processing Technology · 年份：2025 · DOI：10.1016/j.fuproc.2025.108217 · 被引用次数：11 · 研究领域：Zeolite Catalysis and Synthesis、Catalysis and Hydrodesulfurization Studies、Catalytic Processes in Materials Science

In this paper, a one-dimensional ten-membered ring microporous molecular sieve ZSM-48 is employed as a model catalyst, with the number and positional distribution of acid sites in ZSM-48 molecular sieve adjusted by regulating the temperature of templating agent exfoliation. XRD, FT-IR, SEM, TG, NH 3 -TPD, N 2 adsorption-desorption, and the zero-length column (ZLC) method are used for characterization and analysis. The decrease in the distribution depth of acid sites within the microporous channels of ZSM-48 will not only significantly affects the hydroisomerization performance of n -dodecane (resulting in a final yield of isododecane of more than 80 %) but also influences the yield ratio of multi-branched and mono-branched isomers. After the conversion is stabilized, the yield ratio of multi-branched to mono-branched isomers for Z-48-350 is 1.4 to 2.1 times higher than that for Z-48-550. Furthermore, acid site distribution depth profoundly influences reactant diffusion, with Z-48-120 exhibiting a 115 % higher effective diffusion constant than Z-48-550 at 140 °C. Shortening the distribution depth of acid sites in the micropores does not significantly change the product distribution of n -dodecane monomethyl isomers but markedly suppresses the cracking reaction due to reduced diffusion limitation of olefinic intermediates. This enables efficient and selective hydroisomerization of long-chain n -alkanes. • The distribution of acidic sites in ZSM-48 is adjusted by regulating the ...