2-06　詳細な化学を考慮した噴流床石炭ガス炉における多環芳香族化合物やすす生成のシミュレーション

抄録

CO₂ recirculation in the oxy-fuel Integrated Coal Gasification Combined Cycle (IGCC) system is essential for continuous use of coal in the future. This study presents a detailed kinetic investigation into coal gasification under O₂-N₂ and oxy-fuel (O₂-H₂O, O₂-CO₂) gasifying agents. The effects on polycyclic aromatic hydrocarbons (PAHs) and soot formation in the reductor of a two-stage entrained flow gasifier were simulated using CHEMKIN. The detailed chemical kinetic model includes 202 species, 1,351 gas-phase reactions, and 101 surface reactions. The numerical results showed that the oxy-fuel blown modes promoted tar reforming to complete elimination at 1,200°C (<1.5mg/Nm^₃). Because of a different tar conversion behavior, the O₂-H₂O blown mode provided a more potent tar-yield inhibition. In the case of soot formation, the amount of soot decreased under oxy-fuel blown modes. This behavior resulted from hydrogen abstraction and C₂H₂ addition (HACA) surface growth, and nucleation rate reductions. Also, the PAHs condensation had a weak effect on the soot formation rate among different gasifying agents. This study promises a better gasification process design for a two-stage entrained flow gasifier in an oxy-IGCC system.