(336h) Process Development for the Production of Bioethylene from Biomass Via Gammavalerolactone

Biomass has emerged a potential replacement to fossil fuels for the production of biochemicals because these chemicals are renewable and environmentally friendly. Bio-based Ethylene has been produced thermochemically by replacing the methanol and dimethyl ether feedstock from fossil fuels with that produced from gasification of lignocellullosic biomass feedstock. However, developing an energy efficient process is still a challenge. Bio-ethylene has also been produced by enzymatic hydrolysis of biomass but its commercialization is still in its infancy. Furthermore, in countries like South Africa, where a tax rebate for bio-fuel manufacturers exclude bioethanol production, bio-based ethylene production via enzymatic hydrolysis or gasification of lignocellulosic biomass to methanol or ethanol would not be a financially attractive process for manufacturers in such countries. Hence, the chemical conversion process via gammavalerolactone has evolved as an alternative approach to the thermochemical and biotechnological route for biomass valorization to ethylene. However, no existing process via the chemical route has been developed. Hence, this work involves the development of a conceptual process for the optimum production of ethylene from biomass via gamma-valerolactone. A preliminary techno-economic analysis was carried out to determine the best possible route. Typical processes considered are dilute acid pretreatment of sugarcane bagasse; production of levulinic acid via hydrolysis of pretreated sugar cane bagasse; hydrogenation of levulinic acid to gammavalerolactone; decarboxylation of gammavalerolactone to n-butene, metathesis of n-butene to ethylene and product purification. To optimize the overall yield of ethylene from the process, rigorous kinetic models were developed and adopted together with published data on the yield of the intermediate platform molecules. Results from the overall techno economic analysis of the bioethylene process suggests that rich carbohydrate fractions, right choice of operating conditions and different smart approaches are key to obtain an economical viable process. The developed process could be used as a competitive alternative route to the traditional biomass conversion strategies to ethylene.