Comparative Techno-Economic and Life Cycle Assessment of Green Chemistry, Heat Integration, and Water Integration Strategies for an Avocado Oil Biorefinery

Avocado-processing residues can support circular biorefinery development, but optimization strategies must be evaluated with harmonized environmental and economic boundaries to avoid burden shifting. This study compares a baseline thermal-extractive avocado oil biorefinery (S0) with three optimized alternatives: green chemistry (S1), heat integration (S2), and water integration (S3). The comparison uses a functional unit of 1 kg avocado oil at the biorefinery gate, a limited cradle-to-biorefinery-gate boundary, subdivision as the main allocation approach, deterministic life cycle impact assessment, techno-economic assessment, Monte Carlo uncertainty, and allocation sensitivity. Deterministic results show that S2 provides the largest climate-change reduction, decreasing impacts from 3.73 to 1.65 kg CO2 eq kg−1 oil (−55.8%), while also improving economic performance with the highest ROI (100.6%), IRR (55.0%), and the shortest simple payback time (1.75 years). S3 provides the strongest deterministic water-related benefit within the selected LCIA categories, reducing freshwater eutrophication by 85.9% and water use by 10.0% relative to S0. S3 shows a clear freshwater-eutrophication advantage over S0 and S1, with non-overlapping uncertainty intervals. Its marine-eutrophication benefit is more modest, as the intervals partially overlap with those of S0. In contrast, S1 increases climate change by 15.3% and marine eutrophication by 11.1%, indicating that solvent substitution is not automatically environmentally preferable when upstream solvent burdens are included. The results demonstrate that heat integration is the most promising economic and climate-mitigation lever, whereas water integration is the most robust eutrophication-mitigation lever. The main contribution is an uncertainty-aware LCA-TEA framework that distinguishes criterion-specific scenario advantages rather than assigning a single universal best configuration.