Simulation of partial oxidation of natural gas with detailed chemistry: Influence of addition of H2, C2H6 and C3H8

The partial oxidation (POX) of natural gas to produce acetylene was studied using detailed chemistry simulation to determine the influences of adding H2, C2H6 and C3H8 to the CH4 feed. Four detailed chemistry mechanisms, codenamed GRI 3.0, GRI 486, Petersen, and Curran, for describing the POX of natural gas under fuel-rich conditions were evaluated by comparing calculated results with ignition delay time and homogeneous oxidation data. The Curran mechanism gave the best performance, and was further used to examine the influences brought about by changes in the natural gas composition due to the addition of H2, C2H6 and C3H8. The addition of H2, C2H6 and C3H8 reduced the consumption of natural gas per ton of acetylene produced, and would enhance the economy of the POX process and help use up excess H2, C2H6 and C3H8 from other processes in chemical plants. For natural gases that contain small amounts of higher hydrocarbons, the adding of H2, C2H6 and C3H8 significantly decreased the ignition delay time, and the residence time of the feed in the mixing zone has to be reduced when adding these species to avoid uncontrolled combustion.