Life cycle assessment of bioethanol production from sugarcane bagasse using a gasification conversion Process: Bibliometric analysis, systematic literature review and a case study

A new integrated methodology to estimate environmental impacts of bioethanol production from sugarcane bagasse was developed for Mexico. The methodology included five modelling phases: (i) a bibliometric analysis and systematic literature review using peer-review journals, and world citation databases; (ii) a simulation of the gasification process to produce bioethanol; (iii) a life cycle inventory gathered from simulation, literature and Ecoinvent data sources; (iv) a life cycle assessment (LCA) of the bioethanol production stages (raw material extraction, transportation, sub-product extraction, biofuel production, biofuel use in vehicles, and refinery construction and decommissioning), the cumulative energy demand, and water footprint; and (v) the analysis of the major environmental burdens.After a comprehensive searching in Web of Science and Scopus, 55 articles dealing with the state-of-art of the main research subjects for the time period 2008 - 2021 were compiled. The bioethanol production was simulated by using the Aspen Plus v11 software, where a yield of 0.42 L bioethanol per kg of bagasse was estimated for a production of 1,000 L/h and a purity of 98.6 %. In response to the limitations observed in previous environ-mental evaluations conducted for the bioethanol production, the present LCA work was carried out from a robust cradle-to-grave perspective to quantify the major environmental burdens, and the cumulative energy demand and water footprints. Biofuel use in vehicles (70 %) and biofuel production (25 %) stages present the highest contributions for the GWP impact category, which was totally quantified as -26.7 kg CO2-eq/L. When a cradle -to-gate perspective was modelled, this amount was significantly reduced (-8.4 kg CO2-eq/L). For other impact categories evaluated, the highest contributions corresponded to the biofuel production (55 % -95 % for ADP, MAETP, EP, ODP, and POP), and raw material extraction stages (70 % -100 %: LC, HTP, FAETP and TETP). A comparison among previous LCA studies reported for gasification was discussed. This investigation constitutes the first study applied for bioenergy in Mexico from a successful coupling of LCA with process simulation as strategic tools for the evaluation of the environmental sustainability of bioethanol production.

Automated summary

A new integrated methodology was developed to estimate the environmental impacts of bioethanol production from sugarcane bagasse in Mexico. The methodology included five modelling phases: bibliometric analysis, simulation, life cycle inventory, life cycle assessment, and analysis of major environmental burdens. The study found that the biofuel production and biofuel use in vehicles stages had the highest contributions to greenhouse gas emissions.