Detailed kinetic modeling of acetylene decomposition/soot formation during quenching of coal pyrolysis in thermal plasma

A detailed chemical kinetic mechanism based on the Appel-Bockhorn-Frenklach (ABF) model was established to describe acetylene decomposition, ethylene formation, and soot formation during quenching in coal pyrolysis to acetylene process. The predictions agreed well with the reported acetylene pyrolysis experimental data. Numerical simulations were then performed to deeply understand the reaction behaviors during quenching of coal pyrolysis in thermal plasma, and to optimize the quenching design for better heat recovery. Two key operating parameters of quenching, i.e., the temperature after quenching and the quenching rate, were studied in detail and optimized after the kinetics were validated. The simulation results also proved that hydrogen can promote the formation of ethylene and inhibit the condensation of acetylene during quenching. In particular, in-depth discussion of acetylene decomposition and ethylene formation using this detailed kinetic mechanism combined with thermodynamic method provided a comprehensive understanding of the thermodynamics and kinetics interpreting pilot plant experimental data. - Highlights: • A detailed kinetic model for C₂H₂ decomposition and soot formation is established. • Two key operating parameters of quenching are studied in detail and optimized. • Effects of H₂ on C₂H₄ formation and C₂H₂ condensation during quenching are discussed. • A comprehensive understanding of the pilot plant experimental data is achieved.