| Residence time distribution(RTD) was an important parameter for characterizing the mixing performance of a reactor. It reflected the time history of the heat, shear or chemical conditions for the materials under processing. The RTD of twin-screw extruders (TSE) was obtained by experimental measurement generally, while all of the measurement method was offline in our domestic studies without exception.Using a fluorescence monitoring device, the RTD of a co-rotating TSE was measured online, after the former was verified about its reliability. The die and the screw configurations were designed to match the online measurement. On the basis of the data obtained by the online measurement, the effects of the operation parameters on the global RTD were investigated. Combination with flow models, their abilities to describe the flow in TSE was investigated too. On the basis of the theory of numerical linear algebra, a deconvolution method was constructed to deal with two experimental RTD curves(partial and total RTD curves) to obtain the local RTD. Then the effects of the operation parameters and the staggering angles of the kneading blocks on the local RTD were investigated. The error was analyzed with a system consisting of a CSTR and a TLFR when the statistic independence didn't exist at the boundary that connected two subsystems.The investigation results of global RTD showed that the mean residence time decreased with the feed rate increasing, but the effects on the axial mixing intensity weren't obvious. The mean residence time decreased with the screw speed increasing, and the axial mixing intensity increased slightly. The DBFC model could describe the flow in TSE better than the BFC and TIS model did. The numerical linear algebra deconvolution method was a useful method to obtain the local RTD, verified by ideal reactor systems. Kneading blocks with negative staggering angles had greater axial mixing abilities than positive ones, and the residence time was longer too.
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