Journal of Thermal Analysis and Calorimetry, 2026 (SCI-Expanded, Scopus)
This research experimentally investigates the thermal behaviour, model-free kinetic parameters and catalytic influences of copper nanoparticles (Cu-NP) and limestone on the combustion of crude oil under controlled laboratory conditions. Crude oil samples (=10 mg) were blended with Cu-NP at mass concentrations of 10% and 20% and analysed using thermogravimetric analysis (TG/DTG) at heating rates of 5, 10, 15, 20 and 25 °C min−1 under atmospheric conditions. Results showed that increasing heating rates shifted peak temperatures in the low-temperature oxidation (LTO) region from 161.7 to 213.1 °C and in the high-temperature oxidation (HTO) region from 513.6 to 573.8 °C. The LTO stage accounted for the majority of mass loss (78.4–86.5%), highlighting its dominant role in the oxidation process. The addition of Cu-NP significantly modified the combustion behaviour by narrowing reaction intervals and lowering peak temperatures. Kinetic parameters determined using the Kissinger–Akahira–Sunose (KAS) and Ozawa–Flynn–Wall (OFW) methods revealed substantial reductions in activation energy from approximately 208 kJ mol−1 for pure crude oil to about 59–68 kJ mol−1 for the 10 mass% Cu-NP blends confirming the strong catalytic effect of nanoparticles. Experiments incorporating crushed limestone to simulate reservoir conditions showed that limestone increased activation energies and residual mass due to its thermal buffering behaviour, while the combined limestone–Cu-NP system exhibited intermediate kinetic characteristics. These findings provide new insights into how Cu-NP and carbonate minerals influence crude oil combustion behaviour and highlight the potential of nanoparticle-assisted processes for improving in situ combustion (ISC) and enhanced oil recovery (EOR) operations.