Development of the Reduced Chemical Kinetic Mechanism for Combustion of H2/CO/C1-C4 Hydrocarbons

In this study, a reduced 50 species 373 elementary chemical mechanism is developed for the high-temperature combustion of H-2/CO/C-1 -C-4 compounds. The reduced skeletal mechanism, based on the detailed skeletal USC 2.0 mechanism (111 species, 784 reactions), is used to study the ignition and combustion characteristics of the H-2/H-2-CO and C-1-C-4 hydrocarbons. It is found that the reduced skeletal mechanism can reproduce the results from the detailed USC 2.0 mechanism with a maximum error of less than 12% in the ignition delay times under a range of operating conditions with P = 1-20 atm, T = 900-2000 K, and phi = 0.3-2.0. The applicability of the reduced skeletal mechanism is then demonstrated numerically in an industrial gas swirl burner for a 100% C3H8 + air non-premixed turbulent swirl-stabilized flame. The profiles of radial temperature and mole fraction of CO at various axial distances are validated with existing experimental data and are found to be in good agreement. It is therefore established that the reduced skeletal mechanism can be utilized for rapid implementation in a commercial computational fluid dynamics (CFD) package for combustion analysis. It is found that the central-processing-unit (CPU) time cost of the skeletal mechanism is about one-third of that of the detailed USC Mech 2.0 mechanism for the ignition delay and laminar flame speed simulations and is about half of that of the detailed USC Mech 2.0 for non-premixed CFD simulations using a laminar flamelet approach. The present results demonstrate that the reduced skeletal mechanism can provide better scope for studying the combustion characteristics of C-1 -C-4 hydrocarbons at different pressure conditions and compositions.

Automated summary

The study developed a reduced chemical mechanism for high-temperature combustion of H-2/CO/C-1-C-4 compounds, which can accurately reproduce ignition and combustion characteristics. It has been validated through numerical application in an industrial gas swirl burner and shown to provide better scope for studying the combustion characteristics of C-1-C-4 hydrocarbons under different pressure conditions and compositions.