Theoretical study on flow and radiation in tubular solar photocatalytic reactor

Wei, Qingyu; Wang, Yao; Dai, Bin; Yang, Yan; Liu, Haijun; Yuan, Huaijie; Jing, Dengwei; Zhao, Liang

doi:10.1007/s11708-021-0773-9

Cited by 5 publications

(4 citation statements)

References 24 publications

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“…It has been observed that a decrease in the water table stimulates the PA of semiconductor minerals, leading to an increase in semiconductor mineral concentration. Considering semiconductor minerals as the “catalyst” of soil carbon mineralization, the concentration of this “catalyst” undoubtedly plays a crucial role in determining its catalytic efficiency (Wei et al, 2021). In addition, the intensity of light also plays a crucial role in the PA of semiconductor minerals (Cheng et al, 2023).…”

Section: Discussionmentioning

confidence: 99%

Falling water tables reduce peatland semiconductor minerals' capacity for preserving carbon

Zeng,

Cao,

Bai

et al. 2023

Land Degrad Dev

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Semiconductor minerals in peatland play a significant role in the stability of the soil carbon pool. Nevertheless, the ecosystem‐scale importance of semiconductor minerals distribution and their influence on carbon stability in peatlands is still to be determined. Therefore, this study investigated the spatial distribution of semiconductor minerals and their photoelectrochemical activity (PA) in three peatlands with distinct water tables (Equisetum‐swamp [−2.0 cm], Caltha‐meadow [−8.0 cm], and Carex‐meadow [−13.8 cm]). The results indicate that the peatlands of the Qinghai‐Tibet Plateau mainly contain hematite (4.64 wt%), brookite (0.71 wt%), baddeleyite (0.23 wt‰), and zincite (0.10 wt‰); hematite content is the main mineral in peatland. And significantly increased with the decrease of the water table; the photoelectrochemical examination showed that the band gap of semiconductor minerals displayed Caltha‐meadow > Equisetum‐swamp > Carex‐meadow, and the carrier concentration displayed Carex‐meadow > Equisetum‐swamp > Caltha‐meadow, and Carex‐meadow exhibits a steady photocurrent density (0.3 μA/cm2) under light. This suggests that peat soils exhibit an improved photoelectric response with water table drawdown, which would promote the potential for soil carbon mineralization; structural equation model analysis showed that hematite had a significant positive effect on soil organic carbon (SOC), while the PA of semiconductor minerals had a significant negative effect on SOC. That is, semiconductor minerals can not only protect SOC by adsorption but also accelerate organic carbon mineralization by photo‐catalytic generation of reactive oxygen species. Therefore, the decrease in the water table increases the PA of semiconductor minerals, which will weaken the protective effect of semiconductor minerals on soil carbon through adsorption and other means.

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Section: Discussionmentioning

confidence: 99%

Falling water tables reduce peatland semiconductor minerals' capacity for preserving carbon

Zeng,

Cao,

Bai

et al. 2023

Land Degrad Dev

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“…In this study, the discrete ordinates method (DOM) is employed to solve the RTE. Previous research has predominantly used the P1 approximation [30] and six-flux method [31] for solving radiation transfer in photocatalytic reactors. However, the P1 approximation method is known for its lower accuracy, and determining the phase function required in the Six Flux Model can be challenging, particularly for particle suspension systems.…”

Section: Discrete Ordinates Methodsmentioning

confidence: 99%

“…It is worth noting that in this study, solar radiation is coupled as a boundary condition into the energy equation, allowing for the analysis of natural convection phenomena induced by solar radiation. This approach serves as a valuable complement to previous research efforts [28][29][30][31].…”

Section: Euler-euler Two-fluid Flow Modelmentioning

confidence: 96%

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A Numerical Case Study of Particle Flow and Solar Radiation Transfer in a Compound Parabolic Concentrator (CPC) Photocatalytic Reactor for Hydrogen Production

Geng,

Wei,

Luo

et al. 2024

Catalysts

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Compound parabolic concentrator (CPC) photocatalytic reactors are commonly used for photocatalytic water splitting in hydrogen production. This study aimed to gain a better understanding of the physical processes in CPC photocatalytic reactors and provide theoretical support for their design, optimization, and operation. The analysis involved the ray tracing approach, Euler–Euler two-fluid model, and discrete ordinates method (DOM) to study solar radiation transfer and particle flow in the reactor. The distribution of solar radiation on the receiving tube’s surface after CPC concentration was obtained by conducting the ray tracing approach. This solar radiation distribution was then coupled into the Euler–Euler two-fluid model to solve for the natural convection flow field, the temperature field, and particle phase volume fraction distribution inside the receiving tube over a period of 120 s. Lastly, the discrete ordinates method (DOM) was used to analyze the transfer of radiation inside the receiving tube at different times, obtaining the distribution of local volume radiative power absorption (LVRPA) and the total radiative power absorption (TRPA) inside the tube. The results showed that the TRPA reached its maximum at 120 s, accounting for 66.61% of the incident solar UV radiation. According to the above results, it could be suggested that adopting an intermittent operation mode in CPC photocatalytic reactors is reasonable and efficient.

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A Comprehensive Review of Solar Photocatalysis & Photothermal Catalysis for Hydrogen Production from Biomass: from Material Characteristics to Engineering Application

Lei,

Wang,

et al. 2024

Chemistry A European J

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Biomass photoreforming is a promising way of producing sustainable hydrogen thanks to the abundant sources of biomass feedstocks. Solar energy provides the heat and driven force to initial biomass oxidation coupled with H2 evolution. Currently, biomass photoreforming is still far from plant‐scale applications due to the lower solar energy utilization efficiencies, the low H2 yield, and the lack of appropriate photoreactors. The production of H2 from photoreforming of native biomass and platform molecules was summarized and discussed with special attention to the prospects of scaling up the catalysis technology for mass production of hydrogen. The types of photoreforming including photocatalysis and photothermal catalysis were discussed consequently considering the different requirements for photoreactors. We also reviewed the photoreactors that support biomass photoreforming. Numerical simulation methods were implemented for the solid‐liquid two‐phase flow and inter‐particle radiative transfer involved in the reaction process. Developing concentrated photothermal catalytic flowed reactors is beneficial to scale‐up catalytic hydrogen production from biomass.

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Theoretical study on flow and radiation in tubular solar photocatalytic reactor

Cited by 5 publications

References 24 publications

Falling water tables reduce peatland semiconductor minerals' capacity for preserving carbon

Falling water tables reduce peatland semiconductor minerals' capacity for preserving carbon

A Numerical Case Study of Particle Flow and Solar Radiation Transfer in a Compound Parabolic Concentrator (CPC) Photocatalytic Reactor for Hydrogen Production

A Comprehensive Review of Solar Photocatalysis & Photothermal Catalysis for Hydrogen Production from Biomass: from Material Characteristics to Engineering Application

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