Operating conditions to maximize clean liquid fuels yield by oligomerization of 1-butene on HZSM-5 zeolite catalysts. (15th September 2020) - Díaz, Marta
Abstract: The effect of operating conditions has been extensively studied for the selective oligomerization of 1-butene to clean synthetic liquid fuels. HZSM-5 zeolite (SiO2 /Al2 O3 ratio = 30–280) based catalysts provided with a hierarchical porous structure have been tested in a fixed bed reactor under the following conditions: 175–325 °C; 1.5–40 bar; space time, 0.5–6 gcatalyst ·h molC −1 . Special attention has been paid to individual and lumped gaseous and liquid product distribution (which have been characterized by gas chromatography, GC × GC/MS and simulated distillation), as well as to catalyst stability, by performing long duration experiments (20 h). An optimum region to maximize both naphtha (C5-11, >40%), and diesel (C12-20, >20%) yields has been established at 250–275 °C and 30 bar for space time values of 2–4 gcatalyst h molC −1 . Furthermore, the catalysts have tended to a pseudo-stationary deactivation state after 5 h on stream, where the coke deposited on the spent catalysts is mainly composed of adsorbed bulky oligomers (determined by TPD-N2 ), with low coke contents ∼1.0–1.5 wt% (determined by TPO). Graphical abstract: Image 1 Highlights: 1-Butene oligomerization to fuels on HZSM-5 catalysts with hierarchical porosity. Wide range of operating conditions studied: temperature, pressure and space time. Operating maps (temperature, pressure and space time) provided to boost naphtha (>40%), and diesel (>20%) yield. Catalysts tended to a pseudostable deactivation state after 5 h on stream. Coke mainly composed of retained oligomers (soft coke) and low hard coke.