Model-Based Formulation of Biofuel Blends by Simultaneous Product and Pathway Design

Oxygenated
species obtained from the selective chemo-catalytic refunctionalization
of lignocellulosic materials and rationally formulated mixtures thereof
can be tailored to the needs of advanced internal combustion engine
concepts like low temperature compression-ignition or highly boosted
spark-ignition combustion. In the present contribution, we present
a framework for model-based formulation of biofuel blends with tailored
properties by considering the fuel’s molecular composition
as the fundamental design degree of freedom. To this end, optimization-based
reaction pathway screening is combined with mathematical fuel property
prediction by means of structural group contribution and quantitative
structure–property relationship modeling in order to formulate
and solve an integrated product and pathway design problem. The model-based
approach is envisioned (i) to guide fundamental experimental investigations
of the combustion behavior of blended biofuels toward the most favorable
mixtures and (ii) to identify promising conversion pathways for further
elaboration by means of reaction engineering and conceptual process
design. The latter is ultimately needed to bridge the gap from the
mass- and energy-based molecular level analysis presented here to
a process level analysis addressing the economics of the involved
conversion and separation steps. A case study is dedicated to the
identification of promising blends and respective production routes
for the spark-ignition (SI) engine. The goal here is to produce a
100% bioderived fuel with tailored properties from hexoses and pentoses
of lignocellulosic biomass by utilizing renewable hydrogen from carbon-free
energy sources such as wind or solar to boost the energy of fuel produced
for a given quantity of biomass supplied.