Gasoline Synthesis from Biomass-Derived Syngas Comparing Different Methanol and Dimethyl Ether Pathways by Process Simulation, Based on the Bioliq Process

In the bioliq process, biomass is converted to
gasoline over four steps including pyrolysis, synthesis gas (syngas)
generation via gasification, gas cleaning, and gasoline synthesis via
dimethyl ether (DME). This work aims to investigate the gasoline
synthesis plant of the bioliq process and also alternative process
routes for the conversion of biomass-derived syngas to gasoline via
methanol (MeOH) and DME pathways by process simulation in
Aspen Plus, using a syngas composition adapted from the bioliq
plant and enhanced with makeup H$_2$. The simulations were
established using kinetic models for MeOH, DME, and water−gas
shift (WGS) synthesis based on selected models from the literature
and component yield models for MeOH/DME to gasoline (MTG/
DTG) reactions based on product characteristics from known
gasoline synthesis plants. The selected process routes were compared regarding product mass and energetic efficiencies and H$_2$ and
CO$_2$ balances. The results showed that an optimized bioliq process, i.e., biofuel synthesis via direct DME synthesis with a WGS unit
for makeup H$_2$ supply, is efficient in terms of syngas conversion and gasoline productivity, although it has a drawback concerning
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CO$_2$ generation. For this process, the mass and chemical energy efficiencies of gasoline based on syngas were calculated to be
approximately 15 and 65%, respectively. Comparatively, for the similar process via the MeOH pathway, these efficiencies were found
to be 11 and 50%, respectively. The CO and H$_2$ conversion rates for gasoline synthesis via DME were found to be about 77 and 64%,
respectively, whereas via MeOH, they were obtained as ca. 48 and 28%, respectively. Additionally, the optimized process was scaled
up for production of 100,000 tons/year gasoline and evaluated based on mass and chemical energy and CO$_2$ and element (hydrogen,
carbon, and oxygen) balances. Here, the mass and chemical energy efficiencies of gasoline based on biomass feed were calculated to
be 13 and 35%, respectively.