逆流湍动床生物膜反应器液相混合特性的研究

研究了实验室规模逆流湍动床的水力学特性。以亚硝酸钠作为示踪剂，采用刺激 响应技术，通过测定停留时间分布(RTD)，考察了反应器的内部流动状况。考察了不同固含率（0～0.3）、表观气速（1.1～8.8 mm/s）和表观液速（0.66～1.7 mm/s）对RTD的影响。研究表明，表观气速增大、固含率减小和适当提高表观液速都会使反应器返混增强，更接近CSTR。反应器死区百分率低，结构性能良好；死区百分率与表观气速和液速相关性不强，而与固含率负相关。逆流湍动床的RTD可用轴向扩散模型、等体积多釜串联模型和不同体积2釜串联模型来模拟，这些模型的特征参数Pe、N和α分别为1.25～1.79、1.46～1.67和0.74～0.90。

Liquid mixing in an inverse turbulent bed biofilm reactor

The hydrodynamic characteristics in a laboratory scale inverse turbulent bed reactor (ITB) were studied.In order to characterize internal flow in the reactor, the residence time distribution (RTD) was obtained by the stimulus response technique using sodium nitrite as a tracer. Different solid hold-up (0～0.3), air superficial velocity (1.1～8.8 mm/s) and liquid superficial velocity (0.66～1.7 mm/s) values were assayed in RTD experiments.The results show that with the increase of air superficial velocity, decrease of solid hold-up and moderate increase of liquid superficial velocity, the characteristics of ITB are approximating to that of constant flow stirred tank reactor.The percentage of dead space in the reactor, independent of air or liquid superficial velocity and negatively related to solid hold-up, is so low that the structural performance of ITB is excellent. The hydrodynamic of the ITB is well represented by axial dispersion model, tank-in-series and a model that considers the reactor as two mixed tank of different volumes in series, whose model parameters, Pe,N and α, is 1.25～1.79，1.46～1.67 and 0.74～0.90 respectively.