Indra Mamad Gandidi, Asep Bayu Dani Nandiyanto, Qori Zulia Rahma, Daddy Budiman, Sukarni Sukarni, Dwi Aries Himawanto, Susanto Susanto, Gunawan Budi Santoso, Arinal Hamni
An integrated two-step co-pyrolysis (ITSC) process was developed to valorize heterogeneous municipal solid waste (MC-MSW) co-processed with Indonesian brown coal (BC), employing unmodified natural mineral catalysts (kaolin, dolomite, zeolite) for vapor-phase upgrading to improve bio-oil properties. The MC-MSW: BC blend (4:1, w/w) underwent pyrolysis at 550 °C; resulting vapors (paraffins, olefins, aromatics) were catalytically upgraded and analyzed using GC–MS and standardized ASTM protocols (ASTM D445 for viscosity, ASTM D4052 for density, ASTM D92 for flash point, ASTM D5865 for calorific value). Kaolin produced the highest liquid yield (44.0 wt%), outperforming dolomite (36.0 wt%) and zeolite (32.4 wt%), while suppressing gas (9.0 ± 0.5 wt%) and char (47.0 ± 1.5 wt%) formation compared to non-catalytic runs. Dolomite selectively enriched gasoline-range C5–C12 hydrocarbons (up to 73.1%), whereas zeolite favored aromatic enrichment (65.5%) albeit with greater oxygenated residues. Kaolin promoted paraffinic fractions (28.0%) and eliminated acidic species, yielding liquids with high heating values (9,800–9,900 kcal/kg) and improved energy recovery (output/input ratio up to 5.3). Life-cycle carbon assessment, performed using SimaPro v9.0 with IPCC 2013 GWP 100a methodology, indicates up to 1.90 t CO₂-eq avoided per ton of MSW relative to landfilling or incineration. Collectively, the ITSC configuration coupled with low-cost natural catalysts offers a scalable, context-sensitive pathway for decentralized waste-to-fuel conversion: kaolin provides the most balanced performance for fuel-grade liquids, while dolomite and zeolite enable tailored routes toward fuel blending or chemical valorization for sustainable energy. © The Author(s), under exclusive licence to Springer Nature Japan KK, part of Springer Nature 2026.
Energy and Bioprocess Technology Laboratory, Department of Chemical Engineering, Universitas Pendidikan Indonesia, Bandung, 40154, Indonesia; Energy Research on Green Material, Innovation & Application (ENERGIA), Faculty of Technology and Industrial Education, Universitas Pendidikan Indonesia, Bandung, 40154, Indonesia; Department of Mechanical Engineering Education, Universitas Pendidikan Indonesia, Bandung, 40154, Indonesia; Department of Mechanical Engineering, Politeknik Negeri Padang, Padang, 25164, Indonesia; Center for Renewable Fuels Research (CRFR), Department of Mechanical and Industrial Engineering, Universitas Negeri Malang, Malang, 65145, Indonesia; Center of Advanced Materials for Renewable Energy (CAMRY), Universitas Negeri Malang, Malang, 65145, Indonesia; Department of Mechanical Engineering, Universitas Sebelas Maret, Jalan Ir. Sutami 36Kentingan, Jebres, Surakarta, 57126, Indonesia; Vocational Program of Teknika, Politeknik Maritim Negeri Indonesia, Jl. PTP. Ngobo, Desa Wringin Putih, Kecamatan Bergas, Kabupaten, Semarang, Indonesia; Department of Mechanical Engineering, Universitas Lampung, Jl. Soemantri Brojonegoro No. 1, Bandarlampung, 35145, Indonesia
