Study On The Cold Model Experiment And Computational Simulation Of Multiphase Monolithic Reactors

With the development of industrial traditional gas-liquid three-phase reactor,it is could not meet the needs of production.Their shortcomings are large energy consumption,small surface area and other shortcomings.The emergence of structured reactor is a good solution to the above problems,and has good mass transfer performance.In-depth study of structured reactors is of great significance to promote the development of gas-liquid-solid three-phase reactions.In this paper,the distribution and transfer properties of gas-liquid in reactor bed are studied in depth,and cold-mode test method and computational fluid dynamics method are adopted.Firstly,The cold model experiment was carried out on the bed in two different monolith packing under water and air.The pressure drop,liquid holdup and liquid volume mass transfer coefficient were studied in Taylor flow regime,focusing on the effects of four distributors(nozzle,glass bead static distributor,porcelain ring filler distributor and foam distributor)on the flow and gas mass transfer in the bed.The results show that the porcelain ring packing distributor and the foam distributor have a large pressure drop and liquid holdup,and the glass beads center,nozzle is the smallest,but the glass beads are kept close to the porcelain ring and the foam distributor.Friction factor analysis,comprehensive analysis of glass beads distributor performance is the best.According to the analysis of pressure drop and liquid holdup,the corresponding predictive correlation is given.The mass transfer coefficient of each channel is proportional to the superficial gas and liquid velocity.The contribution of the increase of the liquid velocity to the mass transfer coefficient is greater than the gas velocity,and the gas-liquid velocity contributes positively to the mass transfer coefficient.Under the two 400cpsi and 600cpsi mesh beds,the mass transfer performance at 600cpsi is more excellent than 400cpsi.Compared with different distributors,glass bed under the bed mass transfer performance is better than the nozzleAccording to the specific model and experimental conditions of the distributor,the gas-liquid distribution diagram of the glass bead distributor under different apparent gas-liquid velocity was studied by using the computational fluid dynamics method,and the gas-liquid distribution was analyzed.The results show that the gas-liquid distribution shows good uniformity at different apparent gas-liquid velocity.The gas-liquid distribution is divided into five annular regions,and the liquid content in the central and marginal regions is larger than that in the middle zone at different superficial gas-liquid velocity.The gas-liquid content of these five regions reduce for the increase of the superficial gas velocity,but increases with the superficial liquid velocity.The superficial liquid velocity has more effect on the liquid content than the superficial gas velocity.Based on the simulated gas-liquid distribution and the empirical formula of the glass bead distributor,the geometrical structure of the Taylor bubble in the 400cpsi bed is obtained.The radial distribution of mass transfer coefficient is simulated at the different superficial velocity of gas and liquid.The radial distribution of mass transfer coefficient of simulation show that the mass transfer of center region and edge region is smaller than their among region.The radial zone varies slightly at the low superficial liquid velocity with superficial gas velocity and changes at higher superficial liquid velocity,which is similar to that of the whole bed.