The process intensification of CO₂ absorption in Hilbert fractal reactor fabricated by a 3D printer

ABSTRACT

CO₂, as a major greenhouse gas, contributes greatly to the global warming. Increasing the efficiency of CO₂ capture and utilization has becomea worldwide challenge. In the present research, Hilbert fractal reactor was fabricated via 3D printing technology for process intensification of ethanolamine (MEA) CO₂ absorption. The performance of the Hilbert fractal reactor was investigated and compared to the serpentine reactor. For constant gas and liquid flow rates, the CO₂ removal efficiency, the absorption rate, and the assumption of MEA increased with increasing concentration of MEA. In the comparison with the serpentine reactor, the CO₂ removal efficiency in Hilbert fractal reactor is higher than that in the serpentine reactor at the relative low gas flow rate. The continuous bending in the Hilbert fractal reactor enhances the shear stress of the fluids, and the gas phase is segregated into the small bubbles which significantly increase the interface mass transfer. Under the relative high gas flow rate, the residence time of CO₂ is short and the flow pattern in Hilbert reactor turns into the annular flow which adverse to CO₂ absorption rate, and the advantage of Hilbert fractal reactor over serpentine reactor becomes negligible. The maximum CO₂ removal efficiency of 57% was obtained in Hilbert fractal reactor.

KEYWORDS:

• CO₂ absorption
• fractal
• process intensification
• reactor design
• 3D printing

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences and the Key Technical Personnel of Chinese Academy of Sciences, the Ministry of Science and Technology of China (grant 2016YFA0602603). The work was also supported by Frontier Scientific Research Project funded by Shell under contract No. PT19253.