Investigation of CO₂ Photoreduction in an Annular Fluidized Bed Photoreactor by MP-PIC Simulation

Abstract

Carbon dioxide (CO 2 ) photoreduction is a promising process for both mitigating CO 2 emissions and providing chemicals and fuels. A gas–solid two-phase annular fluidized bed photoreactor (FBPR) would be preferred for this process due to its high mass-transfer rate and easy operation. However, CO 2 photoreduction using the FBPR has not been widely researched to date. The Lagrangian multiphase particle-in-cell (MP-PIC) simulation with computational fluid dynamic models is a new and robust approach to explore the multiphase reaction system in the gas–solid fluidized bed. Therefore, the purpose of this paper is to investigate CO 2 photoreduction in the FBPR by MP-PIC modeling to understand the intrinsic mechanism of solid flow, species mass transfer, and CO 2 photoreaction. The MP-PIC models for solid flow in the FBPR were validated by the bed expansion height and bubble size. The results showed the particle stress of the Lun model, the drag of the Ergun-WenYu (Gidaspow) model, and the coefficient of restitution e = 0.95 with the wall parameters e w = 0.9 and μ w = 0.6 are the best fit to the experimental empirical correlations. The MP-PIC models developed in this work proved to be better than the Eulerian two-fluid modeling in the prediction of the bed expansion height and bubble size. It was also found from the simulation results that the maximum radiation intensity is in the half reactor height area, and the photocatalytic reaction mainly occurred around the inner wall. It showed that the gas velocity and catalyst loading were two crucial operating parameters to control the process. The results reported here can provide guidance for the operation and reactor design of the CO 2 photoreduction process.

Две Модели Динамики Лагранжевых Частиц В Канале Вихревой Трубы

“…В работах [3,4] проведено сравнение экспериментальных данных с расчетными результатами, полученными при использовании моделей Лана и Харриса-Крайтона. Показано, что модель Лана лучше подходит для моделирования поведения частиц в случае отсутствия плотной упаковки.…”

Optimization of Yield and Conversion Rates in Methane Dry Reforming Using Artificial Neural Networks and the Multiobjective Genetic Algorithm

“…Barracuda is a commercial computational particle fluid dynamics software that adopts the MP-PIC approach to solve multiphase flows . The attributes of the MP-PIC approach have recently gained considerable interest in various processes, as it has been validated with experimental data, empirical correlations, and industrial applications. − Lu et al employed both the two-fluid model (TFM) and the MP-PIC approach for simulating the carbon dioxide photoreduction in annular CFB by varying the initial catalyst bed height and inlet gas velocity, among other parameters, for envisioning the rise in bed height and size of formed bubbles and determined that the MP-PIC approach surpassed the TFM for the motion of the catalyst within a single cell . Jaiswal et al used an MP-PIC approach to study the properties of bubbles within a CFB hosting a biomass gasifier process while simultaneously altering superficial gas velocities and char loads to identify the optimum gas residence time that corresponds with the peak yield of hydrogen .…”

“…24−26 Lu et al employed both the two-fluid model (TFM) and the MP-PIC approach for simulating the carbon dioxide photoreduction in annular CFB by varying the initial catalyst bed height and inlet gas velocity, among other parameters, for envisioning the rise in bed height and size of formed bubbles and determined that the MP-PIC approach surpassed the TFM for the motion of the catalyst within a single cell. 27 Jaiswal et al used an MP-PIC approach to study the properties of bubbles within a CFB hosting a biomass gasifier process while simultaneously altering superficial gas velocities and char loads to identify the optimum gas residence time that corresponds with the peak yield of hydrogen. 28 The primary equations governed by the MP-PIC method for gaseous and solid phases are listed in the Supporting Information.…”