Analysis of Flow Patterns in Structured 3D printed Packings for Rotating Packed Beds Using γ‑Ray CT.

[NNadir]

OK, I'm in the "Everything All at Once" mode. (I've only seen excerpts of the movie.)

About an hour after learning, for the first time, about rotating packed bed columns, I learn that the technology is over 40 years old.

From Analysis of Flow Patterns in Structured Zickzack Packings for Rotating Packed Beds Using γ-Ray Computed Tomography, Rouven Loll, Lisa Nordhausen, André Bieberle, Markus Schubert, Tobias Pyka, Jörg Koop, Christoph Held, and Gerhard Schembecker Industrial & Engineering Chemistry Research 2023 62 (38), 15625-15634.

Rotating packed beds (RPBs) are an efficient means toward process intensification and were first introduced by Ramshaw and Mallinson in 1981. (1)

This paper appeared a few articles down from the one about which I posted about 40 minutes ago: An Interesting and Novel Approach to Chemical Separations of Which I was Unaware.

"Zickzack" is a German word for things that do not follow linear paths, something else I just learned.

I also posted in this forum earlier today, reference to a paper on 3D printing:

Widening the use of 3D printing: Science

Finally, in this paper, as opposed to ⁶⁰Co, one of my favorite radionuclides, often described as "nuclear waste" ¹³⁷Cs as a γ‑Ray source. ¹³⁷Cs is not a direct gamma emitter, but its decay product ^137mBa emits a γ‑Ray when it decays to the stable ¹³⁷Ba nuclear isomer. (From my perspective ¹³⁷Cs/^137mBa system may be a key to addressing many otherwise intractable environmental problems.)

⁶⁰Co needs to be generated by neutron bombardment of natural cobalt's only stable isotope, Co-59, or alternatively, in theory at least, by bleeding out of ⁶⁰Fe from dissolved old decommissioned steel nuclear reactor cores.

The introductory full text makes me feel a little better about having never heard of rotating packed bed distillation:

Rotating packed beds (RPBs) are an efficient means toward process intensification and were first introduced by Ramshaw and Mallinson in 1981. (1) Since then, RPBs have gained attention in research, and an increasing number of industrial applications in distillation, absorption, or desorption is reported. (2−4) Phase contacting and mass transfer in the RPB packing are intensified through the rotation of the packed bed, ultimately enabling a reduction of the equipment size compared to conventional columns. (3,5) This is advantageous for prefabrication and transport of the equipment from manufacturers to customers (6) for retrofitting of existing plants (3,4,6) and for installations in space-limited environments like offshore applications. (3,4,7,8) As a result of short fluid residence times and the accordingly short response time, RPB technology is promising for applications that require high operation flexibility. (6)

However, the technical maturity of RPBs is still low compared to conventional gravity-driven columns. (2,3,9) A better knowledge about the fluid dynamics in RPBs is required to understand the mass transfer behavior and to derive scale-up rules. (2,9,10) Previous studies (11) revealed severe liquid maldistribution along the radius and circumference of porous packings, such as isotropic metal-foam packings conventionally used in RPBs. Thus, innovative packing designs are required to achieve efficient contacting of the fluid phases throughout the entire volume of an RPB packing. (3,12) In recent years, 3D printing technologies have emerged as a promising tool supporting the development of new packing designs. (13) In addition to anisotropic (14) and multiliquid-inlet (15) wire-mesh packings, various special structured packings (16,17) were suggested to homogenize the liquid distribution.

The so-called Zickzack packing (ZZ packing) belongs to these specially designed structured packings, and the ZZ packing has shown to outperform isotropic porous metal-foam packings and wire meshes in distillation (16) and deaeration (18) experiments. Similar to the structure of the widely used rotating zigzag beds (RZBs), the ZZ packing consists mainly of overlapping concentric baffles, where the upper and lower baffles rotate at the same speed. The tray-like baffle design of the ZZ packing guides the fluid phases through the packing on a zigzag path of approximately constant cross-sectional area, with the aim of distributing the liquid holdup on the baffles (without perforation) uniformly throughout the packing.

I bolded the part that makes me feel better about my ignorance of this tech, and the part that refers to "Everything All at Once," education and verification I'm experiencing.

Reference to ¹³⁷Cs:

2.4. γ-Ray Computed Tomography
To quantify the local liquid fraction at each in-plane position of the rotor, a well-established high-energy γ-ray CT scanner is used that was applied successfully in the past to discover liquid/gas phase distributions in technical equipment, such as viscous couplings (28) and centrifugal pumps, (29) as well as bubble column reactors, (30,31) fixed bed reactors, (32) rotating foam reactors, (33,34) and spinning disc reactors. (35) The scanner essentially comprises a collimated Cs¹³⁷ isotopic source and an oppositely positioned radiation detector arc containing 320 individual detectors positioned with their focus toward the isotopic source. (36)

It's a good day, even near the end of one's life, when one learns new things in an "Everything all at once" fashion.

Have a nice weekend.

Note: I have used the ^x HTML codes for superscripts here in anticipation of the restoration of these codes in the upcoming DU4.

[lapfog_1]

1. more reading for your weekend

https://www.sciencedirect.com/science/article/abs/pii/S0255270120305699

https://www.sciencedirect.com/science/article/abs/pii/S1385894721024591

now that we are in an area that I know something about... i.e. Computational Fluid Dynamics or CFD

Note that I know absolutely nothing about RPB or, indeed, anything about chemistry in general.