Ethylene production from diluted bioethanol solutions

Ethylene production by ethanol dehydration has been investigated over a set of zeolites with BEA structure in acidic form (HAlBEA). The effect on Ni addition (up to 0.03 g/g (3 mass%)) is explored as a means to improve ethylene selectivity limiting the formation of heavier byproducts. The reaction temperature has been varied between 300 and 500 °C and the effect of cofeeding water has been also explored. Both an increase of the operating temperature and of the water/ethanol ratio can improve stability of coking and thus catalyst life. The use of diluted bioethanol solutions was shown to be beneficial for catalyst stability. The effect of possible impurities present in less purified raw materials was also checked by testing two diluted second generation bioethanol solutions (0.5 and 0.9 g/g (50 and 90 mass%)). A first reactor layout and the integration with the bioethanol purification strategy are also proposed, including two purification options which are much less energy demanding than traditional rectification.