Environmental benefits of biomass–plastic co-pyrolysis bio-oil in diesel engines: waste valorization, emission reduction, and sustainability
DOI:
https://doi.org/10.60923/issn.2281-4485/24698Keywords:
Co-pyrolysis, Bio-oil, Waste plastics, Compression ignition engine, Environmental benefits, SustainabilityAbstract
The growing generation of biomass residues and plastic waste, together with the environmental impact of fossil fuel combustion, has intensified research into sustainable alternative fuels for compression ignition engines. This review critically evaluates the environmental benefits of using bio‑oil derived from co‑pyrolysis of biomass and waste plastics as a partial diesel substitute. Co‑pyrolysis synergistically combines oxygen‑rich biomass with hydrogen‑rich plastics, producing hydrocarbon‑enriched bio‑oil with significantly improved fuel properties compared to conventional biomass‑derived pyrolysis oil. Analysis of 41 peer‑reviewed studies shows that co‑pyrolysis bio‑oil has higher heating values (34–47 MJ/kg), lower oxygen content (2.6–15.2 wt%), and reduced acidity. When blended with diesel at 10–30 vol%, these oils give brake thermal efficiencies of 27–34%, approaching or exceeding diesel, while substantially reducing CO (up to 40%), HC (up to 61%) and smoke opacity. NOx emissions show variable trends (‑6% to +25%), depending on feedstock and engine conditions. Catalytic co‑pyrolysis with ZSM‑5, dolomite or activated carbon further improves deoxygenation and aromatic hydrocarbon selectivity. Exergy and sustainability analyses show that co‑pyrolysis oil blends improve sustainability indices (1.34–1.43) and reduce exergy destruction compared to neat diesel. Despite challenges in fuel stability, NOx trade‑offs and feedstock variability, biomass‑plastic co‑pyrolysis bio‑oil represents a viable waste‑to‑fuel pathway that simultaneously addresses waste management crises and reduces dependence on fossil diesel.
References
ALAWA B., CHAKMA S. (2022) Synergism and production of hydrocarbon rich fuel from mixed feedstock through co pyrolysis of LDPE and PP: an assessment of fuel properties, engine performance, and gas emission. Journal of Analytical and Applied Pyrolysis, 168:105736. https://doi.org/10.1016/j.jaap.2022.105736
ALAWA B., CHAKMA S. (2023a) Insight into the engine performance of pyro oil synthesized through catalytic co pyrolysis of mixed waste plastics in the presence of dolomite modified with silica and ZSM 5. Fuel, 354:129190. https://doi.org/10.1016/j.fuel.2023.129190
ALAWA B., CHAKMA S. (2023b) Upgradation, product analysis and engine performance of hydrocarbon fuels produced through pyrolysis of thermoplastic polymers with Si and ZSM 5 modified catalysts. Fuel Processing Technology, 250:107918.
https://doi.org/10.1016/j.fuproc.2023.107918
BRIDGWATER A.V. (2012) Review of fast pyrolysis of biomass and product upgrading. Biomass and Bioenergy, 38:68 94. https://doi.org/10.1016/j.biombioe.2011.01.048
CHOUDHARY J., ALAWA B., CHAKMA S. (2023) Insight into the kinetics and thermodynamic analyses of co pyrolysis using advanced isoconversional method and thermogravimetric analysis: A multi model study of optimization for enhanced fuel properties. Process Safety and Environmental Protection, 173:507 528. https://doi.org/10.1016/j.psep.2023.03.033
DAS A.K., BEHERA S., MOHANTY S., BEHERA N., MOHANTY K. (2025) Performance and emission characteristics analysis of a CI engine fueled with distilled pyrolytic waste plastic oil/ethanol/diesel blends. Envi- ronmental Science and Pollution Research, 32:29309 29316. https://doi.org/10.1007/s11356-023-31091-6
DEMIRBAS A. (2007) Progress and recent trends in biofuels. Progress in Energy and Combustion Science, 33(1):1 18. https://doi.org/10.1016/j.pecs.2006.06.001
DONG Q., ZHANG S., WANG L., LI Y. (2024) Hydrocarbon rich bio oil production from catalytic micro-wave co pyrolysis of peanut shell and LDPE. Catalysts, 14(1):88. https://doi.org/10.3390/catal14010088
EBADI S., LEE J., NAM H., JUNG S., SEO M.W., LEE D., PARK Y.K. (2025) Recent advances in co pyrolysis of algal biomass with waste plastics for the production of upgraded oil. Journal of Analytical and Applied Pyrolysis, 194:107538. https://doi.org/10.1016/j.jaap.2025.107538
FAKHRIIOSEINI S.M., DASTANIAN M. (2013) Predicting pyrolysis products of polyethylene. Journal of Analytical and Applied Pyrolysis, 104:373 379. https://doi.org/10.1016/j.jaap.2013.09.010
HASSAN H., LIM J.K., HAMEED B.H. (2016) Recent progress on biomass co pyrolysis conversion into high quality bio oil. Bioresource Technology, 221:645 655. https://doi.org/10.1016/j.biortech.2016.09.026
KARAGOZ M., UYSAL C., AGBULUT U., SARIDEMIR S. (2020) Energy, exergy, economic and sustainability assessments of a compression ignition diesel engine fueled with tire pyrolytic oil diesel blends. Journal of Cleaner Production, 264:121724. https://doi.org/10.1016/j.jclepro.2020.121724
KUMAR A., ALAWA B., CHAKMA S. (2024) Influence of banana peel waste biomass ratio in co pyrolysis of waste plastics to regulate aromatic content and oxygenated compounds: A study of liquid product characterization and its CI engine performance. Journal of the Energy Institute, 117:101803. https://doi.org/10.1016/j.joei.2024.101803
LV S., WU Z., YANG J., ZHAO W., GAO A., GAO W., YU Y., ZHANG S. (2026) Pyrolytic oil from biomass, plastics, and tires: Production, properties, and tailored upgrading strategies for sustainable application. Renewable and Sustainable Energy Reviews, 226:116480. https://doi.org/10.1016/j.rser.2025.116480
MIANDAD R., BARAKAT M.A., ABURIAZAIZA A.S., REHAN M., NIZAMI A.S. (2016) Catalytic pyrolysis of plastic waste: A review. Process Safety and Environmental Protection, 102:822 838. https://doi.org/10.1016/j.psep.2016.06.022
MIKULSKI M., AMBROSEWICZ WALACIK M., DUDA K., HUNICZ J. (2020) Performance and emission characterization of a common rail compression ignition engine fuelled with ternary mixtures of rapeseed oil, pyrolytic oil and diesel. Renewable Energy, 148:739 755. https://doi.org/10.1016/j.renene.2019.10.161
OASMAA A., CZERNIK S., BRIDGWATER A.V. (2010) Quality control in fast pyrolysis bio oil production and upgrading. Energy and Fuels, 24(12):6548 6554. https://doi.org/10.1021/ef100580b
ONWUDILI J.A., INSURA N., WILLIAMS P.T. (2009) Composition of products from the pyrolysis of polyethylene and polystyrene in a closed batch reactor. Energy and Fuels, 23(12):619 625. https://doi.org/10.1021/ef8008764
PADHY S., DAS A.K., PANDA A.K., GOUDA N. (2025) Utilizing co pyrolysis oil from waste polypropylene and Calophyllum inophyllum seed in diesel engines: combustion, engine performance, and emission analysis. Environmental Science and Pollution Research, 32:31031 31047. https://doi.org/ 10.1007/s11356-025-37255-w
PRASERTPONG P., ONSREE T., KHUENKAEO N., TIPPAYAWONG N., LAUTERBACH J. (2023) Exposing and understanding synergistic effects in co pyrolysis of bio mass and plastic waste via machine learning. Bioresource Technology, 369:128419. https://doi.org/10.1016/j.biortech.2022.128419
RAJAMOHAN S., KASIMANI R. (2018) Analytical characterization of products obtained from slow pyrolysis of Calophyllum inophyllum seed cake: study on performance and emission characteristics of direct injection diesel engine fuelled with bio oil blends. Environmental Science and Pollution Research, 25:9523 9538. https://doi.org/10.1007/s11356-018-1241-x
SENTHIL R., THAMIZHVEL R., SUDAGAR S., AHAMADU H.B.A. (2025) Production of high grade fuels from biomass and waste plastics and its influence in a CI engine. Polymer Bulletin, 82:6095 6114. https://doi.org/10.1007/s00289-025-05740-4
SHADANGI K.P., MOHANTY K. (2014) Co pyrolysis of biomass and plastic waste: A review. Renewable and Sustainable Energy Reviews, 36:299 314. https://doi.org/10.1016/j.rser.2014.04.040
SHARMA A., PAREEK V., ZHANG D. (2015) Biomass pyrolysis – A review of modelling, process parameters and catalytic studies. Renewable and Sustainable Energy Reviews, 50:1081 1096. https://doi.org/10.1016/j.rser.2015.04.193
SINGH D., PAUL A. (2023) Energy, exergy, emission, exergo economic, enviroeconomic, and sustainability analy-sis of diesel engine, fueled by waste cooking oil and waste polyethylene co pyrolysis oil diesel blends. Journal of Cleaner Production, 426:139186. https://doi.org/10.1016/j.jclepro.2023.139186
SURIAPPARAO D.V., BORUAH B., RAJA D., VINU R. (2018) Microwave assisted co pyrolysis of biomasses with polypropylene and polystyrene for high quality bio oil production. Fuel Processing Technology, 175:64 75. https://doi.org/10.1016/j.fuproc.2018.02.019
VENDERBOSCH R.H., PRINS W. (2010) Fast pyrolysis technology development. Biofuels, Bioproducts and Biore-fining, 4(2):178 208. https://doi.org/ 10.1002/bbb.205
WILLIAMS P.T., WILLIAMS E.A. (1999) Interaction of plastics in mixed plastics pyrolysis. Energy & Fuels, 13(1):188 196. https://doi.org/10.1021/ef980163x
ZHANG Q., CHANG J., WANG T., XU Y. (2007) Review of biomass pyrolysis oil properties and upgrading research. Energy Conversion and Management, 48(1):87 92. https://doi.org/10.1016/j.enconman.2006.05.010
ZHOU H., LONG Y., MENG A., CHEN S., LI Q. (2014) Co pyrolysis of biomass and plastic waste: Synergistic effects and product distribution. Fuel Processing Technology, 125:106 114. https://doi.org/10.1016/j.fuproc.2014.03.010
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