Optimization of Polypropylene Waste Recycling Products as Alternative Fuels through Non-Catalytic Thermal and Catalytic Hydrocracking Using Fresh and Spent Pt/Al 2 O 3 and NiMo/Al 2 O 3 Catalysts

Murtadha S. Al-Iessa, Bashir Y. Al-Zaidi, Riaydh S. Almukhtar, Zaidoon M. Shakor and Ihsan Hamawand ()
Additional contact information
Murtadha S. Al-Iessa: Department of Chemical Engineering, University of Technology-Iraq, Alsinaa Street 52, Baghdad 10066, Iraq
Bashir Y. Al-Zaidi: Department of Chemical Engineering, University of Technology-Iraq, Alsinaa Street 52, Baghdad 10066, Iraq
Riaydh S. Almukhtar: Department of Chemical Engineering, University of Technology-Iraq, Alsinaa Street 52, Baghdad 10066, Iraq
Zaidoon M. Shakor: Department of Chemical Engineering, University of Technology-Iraq, Alsinaa Street 52, Baghdad 10066, Iraq
Ihsan Hamawand: Process Operation, Wide Bay Water & Waste Services, Fraser Coast Regional Council, Hervey Bay Qld, QLD 4655, Australia

Energies, 2023, vol. 16, issue 13, 1-29

Abstract: In this work, the conversion of waste polypropylene to alternative fuels (liquid and gas) was performed through non-catalytic thermal and catalytic hydrocracking over NiMo/Al 2 O 3 and Pt/Al 2 O 3 catalysts. The process was carried out in an autoclave batch reactor at a temperature of 450 °C and a pressure of 20 bar, which were selected based on experimental optimization. The spent catalyst was also successfully regenerated at 700 °C under a hot airflow. Experiments were conducted to determine the optimum conditions to completely separate the deactivated catalyst from the solid residue easily. The regenerated catalyst was reused to facilitate the economic cost reduction of the process. The reactivated catalysts have almost the same catalytic properties as the fresh catalysts; this was confirmed by several characterization techniques, such as TGA, XRD, SEM, EDX, BET and FTIR. The produced liquids/gases were quantified and classified into their fractions by the number of carbon atoms and gasoline to diesel ratio using GC/MS. The viscosity, density, API gravity, pour point and flash point of oil cuts were also investigated to evaluate the quality of the resulting liquid from the reactions. The NiMo/Al 2 O 3 catalyst gave the highest liquid hydrocarbons yield of 86 wt%, while the highest weight products of gasoline range hydrocarbon fractions of 49.85 wt% were found over the Pt/Al 2 O 3 catalyst. Almost the same catalytic behavior was found with the regenerated catalysts compared to the fresh catalysts. However, the highest gaseous products at 20.8 wt% were found in the non-catalytic thermal products with an increase in the diesel fuel range of 80.83 wt%. The kinetic model was implemented using six lumps and fifteen reactions, and the apparent activation energies for the gasoline and diesel fractions were calculated. In general, all primary and secondary reactions show greater activation energy values on the Pt/Al 2 O 3 catalyst than on the NiMo/Al 2 O 3 catalyst.

Keywords: HDPE waste plastics; non-catalytic thermal; catalytic hydrocracking; Pt/Al 2 O 3 and NiMo/Al 2 O 3 catalysts; alternative fuels (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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