(525f) Comparison of Processes for Producing OME1 – an Efficient, Economic, and Sustainable E-Fuel?
line-height:115%;color:black">The transport sector contributes more than 20% of
the worldwide greenhouse gas (GHG) emissions and thus requires substantial
emission reductions. In this regard, a promising alternative to fossil fuels
are e-fuels produced from regenerative electricity, water, and CO2. Utilizing
CO2 from direct air capture, industrial point sources, or biomass
processing allows replacing virgin fossil carbon sources. At the same time, some
e-fuels exhibit superior combustion characteristics compared to conventional
fuels. The e-fuel OME1 has outstanding combustion characteristics
for diesel engines: Alternating carbon-oxygen bonds avoid soot formation and
thereby increase engine efficiency, while keeping nitrogen oxide formation at
low levels . OME1 can be produced as e-fuel by simply replacing
its raw material fossil methanol by e-methanol ; however, such a
production concept is energetically inefficient compared to other e-fuels .
In order to overcome this energetic drawback, more efficient production
processes are required.
line-height:115%;color:black">In this study, we consider four OME1 synthesis
routes: the established , oxidative , reductive , and dehydrogenative
 one. Each route is based on methanol from CO2 hydrogenation but
differ in the further reaction pathway. As the detail of process knowledge
varies considerably between the four OME1 routes, a comprehensive
comparison is challenging. Therefore, we compare the routes on three levels
according to the hierarchical methodology shown in Figure 1.
Fig. 1: Hierarchical
line-height:115%;color:black">On Level 1, the raw material consumption for each
synthesis route is calculated using stoichiometric mass balances (i.e.,
assuming no byproducts and complete recycling of unreacted educts or
intermediates). On Level 2, we translate each synthesis route into a process
concept by considering experimental data regarding reaction conditions and
product composition. The use of intermediate-fidelity models  enables the computation
of the overall minimum energy demand. Finally, on Level 3, we use rigorous
models in order to gain more insight into each process concept. These models allow
rigorous optimization and a more detailed analysis of their performance.
line-height:115%;color:black">For the comparison, we introduce three
performance indicators: exergy efficiency, production cost, and GHG emissions. The
exergy efficiency analysis takes into account all material and energy streams
available on the respective hierarchy level. The production cost considers both
operation and capital cost on the most detailed level, whereas only raw
material consumption is considered on the lowest level. On each hierarchy
level, we further conduct a life-cycle assessment for all process concepts in order
to calculate their GHG emissions. Finally, we extend these analyses by
comparing the results for OME1 to other e-fuels.
line-height:115%">The authors gratefully acknowledge funding by the German
Federal Ministry of Education and Research (BMFB) within the Kopernikus Project
P2X: Flexible use of renewable resources exploration, validation, and
implementation of Power-to-X concepts.
 Omari, A., Heuser,
B., & Pischinger, S. (2017). line-height:115%">Potential of oxymethylenether-diesel blends for ultra-low emission
 Deutz, S.,
Bongartz, D., Heuser, B., Kätelhön, A., Langenhorst, L. S., Omari, A., Walters,
W., Klankermayer, J., Leitner, W., Mitsos, A., & Pischinger, S. (2018). Cleaner production of cleaner fuels: wind-to-wheel
environmental assessment of CO2-based oxymethylene ether as a drop-in
fuel. Energy & Environmental Science, 11(2), 331-343.
 Bongartz, D., Burre, J.,
Mitsos, A. (2019). Production of oxymethylene dimethyl ether from hydrogen and carbon
dioxide Part I: Modeling and analysis for OME1. Industrial
& Engineering Chemistry Research, in press.
 Fu, Y., & Shen, J.
(2007). Selective oxidation of methanol to dimethoxymethane under mild conditions
over V2O5/TiO2 with enhanced surface acidity. Chemical
Communications, (21), 2172-2174.
 Thenert, K., Beydoun, K.,
Wiesenthal, J., Leitner, W., & Klankermayer, J. (2016). Ruthenium‐catalyzed
synthesis of dialkoxymethane ethers utilizing carbon dioxide and molecular hydrogen.
Angewandte Chemie, 128(40), 12454-12457.
 Wu, L., Li, B., &
Zhao, C. (2018). Direct synthesis of hydrogen and dimethoxylmethane from
methanol on copper/silica catalysts with optimal Cu+/Cu0 sites. ChemCatChem,
 Bausa, J., Watzdorf, R.
V., & Marquardt, W. (1998). Shortcut methods for nonideal multicomponent distillation:
I. Simple columns. AIChE journal, 44(10), 2181-2198.