Study of High-Pressure Propene Oligmerization over HZSM-5 Zeolite catalyst
Volume Title: 1
Research Institute of Petroleum Industry (RIPI)
The focus of this study has been on the high-pressure oligomerization of propene over HZSM-5 zeolite catalyst at temperature ranging 190 - 350 °C and LHSV (liquid hourly space velocity) = 2.94–6.3 h-1. Na-ZSM-5 zeolite with Si/Al molar ratio 25 was first synthesized and then, using ion-exchange technique, transformed into HZSM-5. To characterize the zeolite, a number of techniques such as XRD, FT-IR, SEM, EDX, TG-DTA, BET and NH3-TPD are used. The oligomerization reaction showed that, by increasing the temperature from 190 to 350 °C, the C7+ hydrocarbons in the product showed an upward trend, whereas above this temperature they leveled out. Similarly, a rise in LHSV caused the C7+ hydrocarbons in the product to decrease. It can be seen from the results that the amount of C7+ hydrocarbons produced over zeolite with Si/Al = 25 at 60 bar, 300 °C and LHSV = 2.94 h-1 is the highest (95 wt %) and is the lowest (71 wt %) at 350 °C with LHSV = 6.3 h-1. Also, with increasing pressure, the rate of production of C7+ hydrocarbons in the product increases up to about 95% wt. The results showed that at high pressures the amount of olefin production increases and the aromatic content decreases. Therefore, it can be concluded that higher pressures are more desirable for the olefin oligomerization process to produce heavier olefins than lower pressures