Planetary boundary analysis in the environmental assessment of corn stover biorefineries

Abstract

Biorefineries offer a promising pathway for sustainable production by utilizing different organic raw materials for further transformation and valorization processes. Nevertheless, the proposed biorefinery structures must be evaluated to determine whether they offer more environmentally sustainable alternatives to current practices. This research aims to assess the potential environmental impact of corn stover (CS) valorization within the framework of the planetary boundaries (PB). Three CS valorization scenarios were proposed and compared with a base case scenario, where CS is traditionally used as mulching in the Sucre region of Colombia. The valorization alternatives were modeled and evaluated using Aspen Plus V14.0 and SimaPro V8.3, relying on the PB-Life Cycle Assessment methodology to quantify the level of PB transgressions. Results showed that the Scenario 0 of CS utilization as mulching remained within the downscaled safe operating space. Notably, biochar utilization in Scenario 1 showed positive results as a carbon sequestration strategy to reduce the environmental impact of CS transformation processes at the PB of climate change. In contrast, Scenario 2, focused only on xylitol production, exceeded the PB for climate change and ocean acidification owing to increased emissions from higher energy needs. These findings highlight the importance of integrating CS valorization processes with biochar conversion, exploiting its potential for agricultural remediation and long-term carbon sequestration. Such practice could enhance the environmental sustainability and feasibility of biorefineries, ensuring they operate within the PB limits while maximizing resource efficiency.