RE-PRO OIL: Conceptual Design of an Integrated Dual-Stage Condensation System for Waste Lubricating Oil Pyrolysis

Abstract

The increasing generation of waste lubricating oil (WLO) and the growing demand for sustainable energy have intensified interest in waste-to-energy technologies that support the achievement of Sustainable Development Goal (SDG) 7 (Affordable and Clean Energy) and SDG 12 (Responsible Consumption and Production). Among available conversion technologies, pyrolysis offers significant potential for recovering valuable hydrocarbon products from WLO; however, existing studies have primarily focused on reactor optimization, catalyst development, and fuel characterization, while limited attention has been given to integrated downstream product separation. This study aimed to develop the RE-PRO OIL (Recovery and Production Oil) conceptual engineering framework for selective fuel-fraction recovery through an integrated dual-stage condensation system. A Systematic Literature Review (SLR) following the PRISMA 2020 guideline and a bibliometric analysis using VOSviewer were conducted on Scopus-indexed publications. From 555 initial records, 200 publications were analyzed bibliometrically and 75 articles were synthesized for engineering development. The analysis identified research hotspots, knowledge gaps, and engineering requirements that were translated into the proposed framework integrating feedstock pretreatment, catalytic upgrading, dual-stage condensation, selective hydrocarbon fraction recovery, gas handling, and future validation. The proposed framework provides a systematic engineering reference for prototype development, selective fuel recovery, and future optimization of WLO pyrolysis systems, thereby supporting sustainable waste-to-energy implementation and circular economy practices.