Intensifying Propylene Production by 1‑Butene Transformation on a K Modified HZSM‑5 Zeolite-Catalyst

The effect operating conditions have in the selective transformation of 1-butene into propylene has been studied on a catalyst of HZSM-5 zeolite (SiO₂/Al₂O₃ = 280) modified with 1 wt % K (of moderate acid strength) and agglomerated with bentonite and alumina. The kinetic runs have been performed in a fixed bed reactor under the following operating conditions: 400–600 °C; space time, up to 1.6 (g_catalyst·h) (mol_C)⁻¹; and butene partial pressure, 0.375–1.35 bar. The kinetic performance has been evaluated at zero time and throughout time on stream in order to find the suitable conditions to maximize propylene yield and selectivity and minimize deactivation by coke. A region of optimum propylene yield (>30%) and propylene selectivity (>50%) has been established for temperatures above 500 °C and space time values depending on the reaction temperature. Furthermore, cofeeding 50% of inert gas is highly recommended in order to attenuate coke deactivation.