The Catalytic conversion of bio-ethanol to ethylene and a pre-feasibility study on commercial plants

Abstract

Ethylene is a major chemical intermediate used in petrochemical industries. It is mainly produced by the steam cracking of the naphtha and ethane feedstocks. Due to the energy crisis, the alternative way of ethylene production from bio-ethanol has received wide attention. Since bio-ethanol can be obtained easily by the fermentation of a sugar or starch source. The ethylene production via catalytic dehydration of bio-ethanol over 0.5 wt% MgHPO4/y-Al2O3 catalyst was investigated. The reaction temperature was varied from 370C to 460 C with various bio-ethanol feed concentration (40-50%, 95%, and 99.5% ethanol), whereas the liquid hourly space velocity (LHSV) was fixed to 1.0 h-1. The results showed that reaction temperature and bio-ethanol conentration in the feed significantly affected the ethanol conversion and ethylene selectivity. The highest yield of ethylene (97.6% ethanol conversion and 93.3% ethylene selectivity) was obtained at the reaction temperature of 460 C with using 95% ethanol as the feed. Furthermore, the prefeasibility on the two commercial plants (Chematur and Petrobras) for ethylene production from bio-ethanol was evaluated. It was found that the two commercial plants for ethylene production from bio-ethanol were not economically feasible with the aim of 15% IRR, due to the high price of ethanol. Additionally, the sensitivity analysis revealed that ethanol and ethylene prices were the sensitive parameters susceptible to the economic feasibility of two commercial processes. However, both plants can be commercially feasible, provided that the ethanol and ethylene prices are 46.5% lower and 38% higher than the current price for Chemature, and 14.5% lower and 12% higher than the current price for Petrobras, respectively.