Abstract
Higher alcohols production from syngas through chemical route has gained attention over the last decade because of characteristics such as: short-time reaction, abundant and lower price feedstocks, the use of lignin (a biomass component that is hardly used) and the almost complete conversion of the initial feedstock. In this route, cleaned and reformed synthesis gas (syngas), formed of carbon monoxide (CO) and hydrogen (H2) is catalytically converted into a mixture of alcohols that after purification can be used as fuel, solvent, or as feedstock for other processes. In this particular case study we use a Cu-based (Cu-O-ZnO-Zr-Fe-Mo-Th-Cs) catalyst, which consists of a modified methanol synthesis catalyst, so as to conceive, simulate, optimize, and analyze a small scale syngas-to-higher alcohols production plant (process capacity of 100 kmo/h of pure syngas). We assume that the WGS (water-gas-shift) reaction reaches equilibrium conditions and the alcohols production follows the ASF (Anderson-Schulz-Flory) distribution. The main advantage shown by this catalyst is the absence of water production, since all the water is consumed by the WGS reaction, on the other hand, the same reaction produces CO2 that can be recovered only coupling another process in order to produce more CO. The final product separation (methanol, ethanol, propanol, butanol and pentanol) is facilitated by the absence of water. After process design and optimization, an energy and yield analysis is discussed while pointing possible solutions and next steps regarding the sustainability of the process.
