非平衡等离子体作用下CH4裂解特性及其反应机理分析OA

Methane cracking driven by electric power holds significant promise in the context of the rapid development of renewable energy.The effects of carrier gas ratio,input power,and inlet gas flow rate on CH4 cracking performance were systematically investigated in a dielectric barrier discharge(DBD)reactor.The variation of temperature distribution and reaction energy intensity were also examined.The experimental results indicate that CH4 conversion and gaseous product formation are promoted by increasing the DBD input power or decreasing the inlet gas flow rate.At an input power of 90 W and an inlet gas flow rate of 200 mL/min,the single-pass CH4 conversion reach 46.6％,with an H2 yield of 23.3％,demonstrating that CH4 cracking is governed by electron induced.While the Joule heating from the inner and outer electrodes is relatively limited.The reaction energy intensity increases as the CH4 conversion decreases.When the inlet gas flow rate increases from 200 to 800 mL/min,the energy intensity rises by approximately 2.8 times,indicating that higher inlet gas flow rates enhance the convective heat transfer and shorten the gas residence time,thereby suppressing deep CH4 cracking.Moreover,BOLSIG+calculations further reveal that CH4 activation is dominated by electron induced vibrational excitation,in which stepwise energy accumulation drives C-H bond dissociation.The energy transfer and species transformation pathways of overall CH4 cracking process,which comprises electron energy injection,vibrational excitation,stepwise dissociation,radical chain extension,and final product formation,can be summarized into three stages,i.e.methane activation,radical evolution,and product formation.