Numerical Simulation Research And Development Of Spiral Plate Fixed Bed Reactor

Fixed bed reactor is widely used in gas-solid catalytic reaction,and is the core equipment of chemical reaction process.In this paper,a new type of fixed-bed reactor suitable for gas-solid phase catalytic reaction was developed by using the structural characteristics of spiral plate heat exchanger.The new fixed bed reactor was numerically simulated by fluent software.The flow and heat transfer characteristics of the reactor under different structural parameters and technological parameters were studied,which provided a reference for the design of a new fixed bed reactor.The main work is as follows:The physical model of spiral plate fixed bed reactor was established,and the flow and heat transfer on the side of heat transfer medium under different inlet velocity,plate spacing and height-diameter ratio were studied by numerical simulation method.The results show that when the inlet velocity increases from 0.4m/s to 1.0m/s,the turbulent kinetic energy,the pressure difference between inlet and outlet and the nusselt number on the side of the heat transfer medium increase gradually with the increase of the inlet velocity,and the drag coefficient decreases.Compared with 0.4m/s,the nusselt number increases by 108%.It shows that the heat transfer performance of the heat transfer medium side is better when the inlet velocity is 1.0m/s.With the increase of plate spacing,the PEC index of the heat transfer medium side of the reactor decreases gradually.The PEC index decreases by about 12% when the plate spacing is16 mm compared with that when the plate spacing is 10 mm,which indicates that the smaller plate spacing is more conducive to heat transfer under the premise of ensuring heat transfer.Change the height-diameter ratio of the reactor.With the increase of height-diameter ratio,the turbulent kinetic energy,pressure difference between inlet and outlet and the nussel number decrease in varying degrees,while the drag coefficient increases.Compared with the height-diameter ratio of 0.603 and 0.862,the PEC index increases by about 31%,so the smaller the height-diameter ratio is more conducive to heat transfer.The reactor reaction side was modeled as porous medium with heat source applied.The influence of feed temperature and feed speed on bed temperature was studied by numerical simulation.The results show that the outlet temperature of the reactor increases gradually as the feed temperature increases from 170 C to 182 C.Theoptimum reaction temperature of the synthetic bed is determined to be 178 C.When the feed temperature is 178 C,the bed temperature decreases with the increase of feed rate.When the feed rate is 0.45m/s,the bed temperature approaches the optimum reaction temperature.The process design and structure design of spiral plate fixed bed reactor were carried out for the synthesis of vinyl acetate by acetylene gas phase method.