【摘要】 在直径为310mm,高2000mm 的环隙气提式环流反应器试验装置中,分别测定了液相和气相的返混特性。以带死区的全混流模型来描述液相流况;建立了气相返混的组合模型,利用此模型可揭示出总体气相返混的形成机理。更多还原

【Abstract】 In a laboratory-scale reactor of diameter 310mm and height 2000mm,the back- mixing of both the liquid-phase and gas-phase were measured. It was found that the liquid circulating ratio（n_c）for the present reactor is 12 and the flow pattern of liquid can be described by a model composed of a mixing tank interconnected with a dead region as shown by ln （C（t））/（C_o）=（-1）/（1-η） t/τ’ The fraction of the dead region decreases as the superficial gas velocity u_g in- creases and it approaches zero when u_g≥7cm/s. The backmixing of the gas phase as a whole can be represented by the axial dispersion model.The Peclet number Pe is nearly independent of the liquid cir- culating velocity,but increases with the increase of u_g. In order to reveal the effect of local backmixing,a combined model has been established and the following relationships were obtained: τ_total=τ_A+τ_D+f（τ_A+τ_B） （σ_t²）_total=（1+f）τ_A²/m+f（1+f）（τ_A+τ_B）²+τ_D² where τ is dimensionless time,m is the number of tanks,f is the circulation ratio and the subscripts A,B and D denote the different regions as showm in Fig.3 respectively.更多还原