Syngas production from sewage sludge–waste oil co-gasification: Thermodynamic and exergy analysis
ENERGY, cilt.364, ss.1-15, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 364
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.energy.2026.142432
- Dergi Adı: ENERGY
- Derginin Tarandığı İndeksler: Applied Science & Technology Source, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO), Scopus, Science Citation Index Expanded (SCI-EXPANDED), Compendex, Environment Index, Geobase, INSPEC, Public Affairs Index
- Sayfa Sayıları: ss.1-15
- İstanbul Üniversitesi-Cerrahpaşa Adresli: Evet
Özet
Sewage sludge is a low-grade feedstock for thermochemical conversion due to its high ash content, low volatile fraction, and low energy density, which restrict syngas quality and thermodynamic efficiency. In contrast, hydrocarbon-rich waste oils provide high chemical energy and reactivity but exhibit instability when processed independently. This study introduces a co-gasification strategy that integrates sewage sludge with waste oils to shift the governing reaction regime from heterogeneous char conversion toward gas-phase reforming, thereby intensifying hydrogen generation and improving thermodynamic performance. Experiments were conducted under varying oxidant types, flow rates, and temperatures to elucidate process behavior. The results demonstrate that co-gasification enhances hydrogen-rich syngas production and improves energy and exergy performance. Under oxygen-blown conditions, hydrogen concentration increased from approximately 42 to 54 vol%, accompanied by increases in CH4 and CO fractions and an improvement in syngas calorific value. Optimal hydrogen-rich syngas production was achieved at 700 ◦C and low oxidant flow rates (0.01–0.05 L min− 1 ), where reducing conditions favored reforming-dominated pathways and elevated H2/CO ratios. Thermodynamic evaluation revealed that the sludge–motor oil system increased first-law efficiency from 0.264 to 0.394 and exergy efficiency from 0.217 to 0.337. Feedstock-specific exergy analysis further indicated that the thermodynamic response of the system was governed by the distribution and recovery of chemical exergy rather than feed mass alone. Furthermore, a multiple linear regression model (R2 = 0.991) described the empirical relationship between syngas composition and calorific value under the investigated operating conditions. Overall, the proposed co-gasification strategy offers a robust pathway for the thermodynamic upgrading of low-grade wastes into hydrogen-rich syngas for advanced energy systems.