Study on flow and heat and mass transfer characteristics of cross-flow poly propylene hollow fiber membrane module

ABSTRACT

Hollow fiber membrane solution dehumidification technology is a new type of dehumidification technology combining solution dehumidification and membrane separation. It is currently widely used in the field of air conditioning dehumidification. In this study, membrane dehumidification technology was applied to low-temperature flue gas dehumidification, and a model of regularly arranged hollow fiber membrane modules was established on the basis of a conjugate heat and mass transfer model. The accuracy of the model was verified by comparing it with literature and experimental data, applying a random arrangement of components. Numerical simulation is carried out by COMSOL software. The flue gas velocity, temperature and water vapor concentration field in the module are coupled together, and the flue gas flow and heat and mass transfer characteristics are affected by the distance between the membrane filament tubes. The dehumidification and cooling efficiency of the randomly arranged hollow fiber membrane module can reach 68.3% and 39.1%,respectively, which Close to 72.1% and 48.7% of regularly arranged components. And the components can be optimized based on the model.

KEYWORDS:

• Hollow fiber membrane
• dehumidification
• numerical simulation
• flue gas
• heat and mass transfer

Acknowledgments

This work is supported by the Natural Science Foundation of Shandong Province (ZR2019MEE015) and the Key Research and Development Plan of Shandong Province (2018GSF117042).

Symbol Description

${\rho }_a$——flue gas density, $\mathrm{k}\mathrm{g}/m^3$

$P$——flue gas side pressure, $\mathrm{p}\mathrm{a}$

${\mu }_a$——flue gas dynamic viscosity, $\mathrm{N}\mathrm{s}/{\mathrm{m}}^2$

$c_{p,a}$——specific heat of flue gas, $\mathrm{J}/\left(\mathrm{k}\mathrm{g}\right)$

$T_a$——flue gas temperature, $\mathrm{K}$

${\lambda }_a$——flue gas thermal conductivity, $\mathrm{W}/\left(m\right)$

$C_a$——water vapor concentration in flue gas, $\mathrm{m}\mathrm{o}\mathrm{l}/{\mathrm{m}}^3$

$D_{va}$——diffusion coefficient of water vapor in flue gas, $m^2/\mathrm{s}$

${\mathrm{D}}_{\mathrm{v}\mathrm{m}}$——diffusion coefficient of water vapor in the membrane, ${\mathrm{m}}^2/\mathrm{s}$

$\mathrm{r}$——.latent heat released by absorption of water vapor, $\mathrm{J}/\mathrm{k}\mathrm{g}$

$\mathrm{A}$——mass transfer area, ${\mathrm{m}}^2$

${\mathrm{M}}_{\mathrm{A}}^{\ast }$——molar mass of water vapor molecules, $\mathrm{k}\mathrm{g}/\mathrm{m}\mathrm{o}\mathrm{l}$

${\lambda }_{\mathrm{s}}$——thermal conductivity of solution, $\mathrm{W}/\left(\mathrm{m}\mathrm{K}\right)$

${\mathrm{T}}_{\mathrm{s}}$——temperature of solution, $\mathrm{K}$

Additional information

Funding

This work was supported by the the fifinancial support from the Natural Science Foundation of Shandong Province [ZR2019MEE015]; the Key Research and Development Plan of Shandong Province [2018GSF117042].

Notes on contributors

Xiaowen Qi

Xiaowen Qi, [email protected], College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, Shandong, China.

Enze Zhou

Enze Zhou, [email protected], College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, Shandong, China.

Lili Ge

Lili Ge, [email protected], College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, Shandong, China.

Siyi Luo

Siyi Luo, [email protected], College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, Shandong, China

Xuefei Wu

Xuefei Wu, [email protected], College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, Shandong, China.