Optimization of Microreactor Design Using Computation Fluid Dynamics
[Thesis]
Chukwudoro, Chiemeka P.
Basha, Omar M.
North Carolina Agricultural and Technical State University
2020
48
M.S.
North Carolina Agricultural and Technical State University
2020
In this work a multi-Eulerian CFD model was used to investigate the effect of different design features on the performance of a microchannel reactor available at NC A&T. The CFD model was used to investigate the effect of the reactor inlet, the mixing internals and the channel designs on the dead zone %, the quality index factor, the cooling requirement and the maximum dimensionless temperature within the microreactor. Subsequently, an analysis was conducted to determine the effect of changing the channel dimensions and on the numbering up of the microchannel reactors to produce 1 bpd. Channel types 5 to 9 showed the highest reduction of dead zone % within the microreactor, with the dead zone % reduced to less than 10% compared to original design, which had a dead zone % greater than 20%. Similarly, channel types 5 to 9 exhibited significantly lower quality index factors, moreover, both the T-inlet and the V-inlet designs exhibited lower quality index factors compared to the straight inlet design. When investigating the effect of channel dimensions on the microreactor performance, there is no significant effect of increasing the channel width on the microreactor performance and operating microchannel reactor at lower Nusselt number results in higher CO conversion. Moreover, increasing the channel width reduced the maximum temperature exhibited in the channel. However, both designs exhibited the same temperature profiles along the channel, with the maximum temperature observed at around 40% of the channel length. Finally, the effect of increasing the y/x stacking ratio, i.e. having more reactor units in parallel compared to series, was investigated. Increasing the y/x ratio will increase the cooling requirement and the maximum dimensionless temperature increase within the unit and will decrease the productivity. Therefore, in order to minimize productivity losses, numbering up in series is the better approach, however further analysis has to be done to delineate heat removal requirements.