A sustainable recovery pathway for palm process residue integrating safety, health, environment, and economic aspects

Oleochemical industry generates substantial amount of palm process residue during the hydrogenation of fatty acids or methyl esters, comprising medium- to long-chain fatty alcohols and alkanes. Recovery of fatty alcohols for commercial utilization as well as the utilization of alkanes for lubricants, jet fuel, as well as gasoline contribute to a circular economy and minimize waste generation. However, conventional separation methods face challenges and incur high costs in separating fatty alcohols from alkanes with overlapping boiling points because sustaining the precise temperature differences required for phase transitions is challenging, especially at high reflux ratio. A promising approach to overcome these limitations is to chemically convert fatty alcohols into derivatives whose boiling points differ markedly from those of alkanes, enabling subsequent separation to be done efficiently through distillation and reducing energy consumption. Alternatively, extractive distillation (ED) can be employed, in which an entrainer is added to modify the relative volatility (α) of fatty alcohols and alkanes, thereby enhancing their recovery efficiency. While efficient separation is crucial, this study also integrates safety, health, and environment (SHE) as well as economic criteria to evaluate the recovery pathways in terms of products and processes. By integrating index based SHE assessments, the analytic hierarchy process (AHP) weighted sum approach was deployed in this study to determine an optimal trade-off between SHE and economic aspects, ultimately developing a recovery pathway that is efficient, economically viable, SHE responsible, and aligned with sustainable manufacturing principles.