Integrierter Produkt-Prozessentwurf für maßgeschneiderte Biokraftstoffe - Vergleich zweier Syntheserouten zur Herstellung von Butyllävulinat -

Abstract:
Since the availability of fossil resources diminishes, biomass is more and more con-sidered as raw material in the production of chemicals and fuels. Butyl levulinate is a promising fuel candidate due to its high oxygen content and less NOx as well as soot emissions during combustion. In this work two different synthesis routes for the pro-duction of butyl levulinate are compared. Butyl levulinate is synthesized by esterfica-tion of levulinic acid and butanol. A promising approach is the “Biomass to Liquid” route (BtL), which is a multiple step process to produce liquid biofuels. In a first step low-molecular intermediates are produced by biomass gasification. The gasification of biomass is a thermal treatment, which results in a high production of gaseous products such as CO and H2 as well as small amounts of char and ash. Air, pure oxygen and water can be used as gasification agent. Afterwards long chain hydro-carbons are produced by Fischer-Tropsch-Synthesis using syngas and then con-verted to butyl levulinate and butanol. Another approach is to preserve the functional units of biomass. Cellulosic biomass is transformed into glucose which is afterwards converted to obtain butanol by fermentation. Furthermore levulinic acid can be pro-duced by the so-called biorefine process. This approach is called “Tailor-Made fuels from Biomass” (TMFB). Both approaches are compared by applying Reaction Network Flux Analysis maxi-mizing the yield of butyl levulinate. Therefore a best case and a realistic scenario are considered. In the best case scenario the reaction path over low-molecular interme-diates results in a higher yield of butyl levulinate since the whole biomass can be used as feedstock. In a realistic scenario the functional unit results in a higher yield since the selectivity of the Fischer-Tropsch synthesis for C5 and C4 hydrocarbons is very low.