Kinetics of Gasification and Co-gasification of Petcoke and Coal

Abstract

Co-gasification of petroleum coke with other carbonaceous material is making significant inroads in the quest for efficient utilization of petroleum coke. In the present work, gasification and co-gasification of petroleum coke and low-grade Indian coal was studied by thermogravimetric analysis at three heating rates, 10, 20, 30 °C min−1 under oxygen atmosphere. Physicochemical characterization of petroleum coke revealed that it contains significantly high fixed carbon and has high calorific value with low ash content vis-a-vis coal sample. It was observed that with the increase in heating rate, the ignition and the burn out temperature also increases. Kinetic parameters were calculated by employing commonly used two model-free isoconversional methods, i.e., Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) based on TGA data. The activation energies of petcoke and blend (petcoke + coal) calculated by KAS and FWO methods were found to be 126.75 and 109.94 kJ mol−1, and 128.3 and 111.85 kJ mol−1, respectively. Activation energy values obtained by both the methods demonstrate that the blend requires lesser energy than gasification of petcoke alone. Gasification of blend was found to follow complex multi-step nature of kinetics. Overall, the findings demonstrate that co-gasification could be a practical approach for energy recovery from the petcoke–coal mixture than gasification of petcoke alone.