Energy efficient simultaneous oxidative conversion and thermal cracking of ethane to ethylene using supported BaO/La₂O₃ catalyst in presence of limited O₂

Abstract

An energy efficient conversion of ethane to ethylene involving simultaneous oxidative conversion (which is exothermic) and thermal cracking (which is endothermic) reactions of ethane in the presence of steam (steam/C₂H₆ mol RATIO=1.0) and limited O₂ (C₂H₆/O₂ mol ratio [greater-or-equal, slanted] 4.0) over a BaO-promoted La₂O₃ supported on low surface area macroporous silica-alumina commercial catalyst carrier has been thoroughly investigated. Influence of various process parameters such as temperature (700-850° C), C₂H₆/O₂ feed ratio (4.0-8.0) and space velocity (50,000-200,000 cm³ g^-1 h^-1) on the conversion, product selectivity and net heat of reactions in the process has also been studied. At all the process conditions, there was no coke deposition on the catalyst. High selectivity ([greater-or-equal, slanted] 85%) for C²⁺ olefins (at 50-60% conversion) can be obtained in the process at a low contact time (<10 ms), particularly for the higher C₂H₆/O₂ ratios ([greater-or-equal, slanted] 6.0) and temperatures ([greater-or-equal, slanted] 800°C). The process exothermicity is decreased appreciably with increasing the temperature and/ or the C₂H₆/O₂ ratio. The net heat of reaction in the process can be controlled by manipulating the C₂H₆/O₂ ratio and reaction temperature. Also, because of simultaneously occurring endothermic and exothermic reactions, the process is highly energy efficient and non-hazardous.