Dissertation
Dissertation > Industrial Technology > Chemical Industry > General issues > Chemical processes ( physical processes and physical and chemical processes ) > Basic theory > Diffusion and mass transfer processes and principles

Experimental Study of Liquid Flow and Axial Dispersion Performance in Multiphase Monolithic Reactors

Author ChenYaZuo
Tutor LiuHui
School Beijing University of Chemical Technology
Course Chemical Engineering and Technology
Keywords Structured multiphase reactor Axial diffusion model Transfer function method Mean residence time 彼克莱number
CLC TQ021.4
Type Master's thesis
Year 2011
Downloads 17
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Structured multiphase reactor with conventional heterogeneous reactor compared with the pressure drop, high mass transfer rate and the large specific surface area and many other advantages, which makes it an attractive alternative to conventional multiphase reactor choice. Therefore, in-depth study of structured multiphase reactor has a very important significance. In this thesis, the different types of structured multiphase reactor liquid flow and axial diffusion properties, in order to provide a sound basis for the reactor design, operation and enlarge. Experiment tap water as the liquid phase, and air as the gas phase, liquid distributor nozzle and the static distribution of glass beads were 0.0283-0.0637m / s superficial liquid velocity, superficial gas velocity of 0.0490-0.2942m / s , and flow to the next operation mode, the monolith 50cpsi, 100cpsi and 400 cpsi three kinds of cell density and the segmented structure of a multiphase reactor were a \Conductance method, measuring different superficial gas and liquid speed \Nozzle liquid distributor within the overall structure of multiphase reactor analysis based on experimental data, the apparent gas, liquid velocity on the degree of axial diffusion effects of mean residence time, bed pressure drop, the average liquid holdup and the length of the average liquid suppository with superficial gas and liquid speed and cell density trend, access to reflect the degree of axial dispersion number of the size of the Bike Lai relational; contrast the two distributions is monolithic and segmented the structured multiphase reactor within the average residence time, bed pressure drop, the average liquid holdup, and the average length of the liquid suppository with the superficial gas, the change trend of the fluid velocity and the axial size of the degree of diffusion. The results show that: the nozzle liquid distributor within the overall structure of multiphase reactor: (1) the degree of axial diffusion with increasing superficial liquid velocity decreases with the increase of superficial gas velocity and increases. (2) superficial liquid velocity is increased, the mean residence time and pressure drop stability decreases, the average bed pressure drop, increases the average liquid holdup and the average length of the liquid suppository; the superficial gas velocity increases, The average residence time, the average bed pressure drop, the average liquid holdup and the length of the average liquid suppository decreases substantially constant pressure drop stability; the cell density increases, the average residence time decreases, bed pressure drop and average liquid holdup increases, the length of the liquid plug along with first increases and then decreases. (3) Bike Lai reflect the the axial diffusion magnitude of the number relational acquired most of the errors are within ± 30% the axial dispersion conditions, be able to better predict structured multiphase reactor. The comparative study results show that: (1) the average residence time, bed pressure drop, the trend of the average liquid holdup and the length of the average liquid suppository segmented structure of multiphase reactor with the apparent gas, liquid speed basically The same trend in the overall structure of multiphase reactor within. (2) use of a nozzle for the liquid distributor, the axial degree of diffusion within the reactor is smaller. (3) In order to reduce the axial diffusion, may be set within the structured multiphase reactor re-distribution segment, but from back mixing occurred energy consumption, etc. comprehensively consider.

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