High-temperature catalytic oxidative conversion of propane to propylene and ethylene involving coupling of exothermic and endothermic reactions

Coupling of the exothermic catalytic oxidative conversion and endothermic t hermal cracking (noncatalytic) reactions of propane to propylene and ethyle ne over the SrO/La2O3/SA5205 catalyst in the presence of steam and limited oxygen was investigated at different process conditions (temperature, 700-8 50 degrees C; C3H8/O-2 ratio in feed, 2.0-8.0; H2O/C3H8 ratio, 0.5-2.5; spa ce velocity, 2000-15000 cm(3) g(-1) h(-1)). In the presence of steam and li mited O-2, the endothermic thermal cracking and exothermic oxidative conver sion reactions occur simultaneously and there is no coke formation on the c atalyst. Because of the direct coupling of exothermic and endothermic react ions, this process occurs in a most energy efficient and safe manner. The p ropane conversion, selectivity for propylene, and net heat of reaction (Del ta H-r) in the process are strongly influenced by the temperature and conce ntration of O-2 relative to the propane in the feed. The C3H6/C2H4 product ratio is also strongly influenced by the temperature, C3H8/O-2 feed ratio, and space velocity. The net heat of reaction can be controlled by manipulat ing the reaction temperature and C3H8/O-2 ratio in the feed; the process ex othermicity is reduced drastically with increasing the temperature and/or C 3H8/O-2 feed ratio.