Microfibrous Entrapment Technology

Microfibrous entrapment enables catalytic and sorptive processes to occur more efficiently than previously imagined or commercially practiced by enhancing physical rate phenomena.

Entrapment Advantages

What are Microfibrous Entrapped Catalysts and Sorbents?

Microfibrous entrapped catalysts and microfibrous entrapped sorbents (MFECs and MFESs respectively) consist of porous, high-surface-area particles immobilized in media made of micron-diameter fibers. The microfibrous media (MFM) may be composed of metal fibers for enhanced heat transfer, ceramic/glass fibers for corrosive environments, or polymer fibers for low-temperature, low-cost applications. Fiber diameters for microfibrous entrapment typically range from 2 to 25 microns and entrapped particle diameters typically range from 40 to 300 microns.

MFEC MFES examples

Images of catalyst and sorbent particles entrapped in sintered microfibrous media

How do MFECs and MFESs work?

MFECs and MFESs provide increased efficiency by enhancing physical rate phenomena that are commonly limited on the micron scale in reactive processes. The catalyst/sorbent particles used in MFECs and MFESs are significantly smaller than the extrudates (1.6-5 mm) widely used in industry, allowing intraparticle resistances to be minimized. The high void fraction of the microfibrous media allows these improvements to be realized with a lower pressure drop than in a packed bed of the entrapped particles. External mass and heat transfer characteristics are also enhanced in MFECs and MFESs because the micron-diameter fibers dominate the flow pattern, especially at low Reynolds numbers, producing conditions analogous to a frozen fluidized bed. MFECs and MFESs share the advantages of fluidized beds in terms of improved mass and heat transfer; however, MFEC and MFES systems are fixed beds, so the process disadvantages of fluidized beds are avoided. With fast mass & heat transfer, reaction rates can be improved by 1-3 orders of magnitude, depending on the specific reaction or process.

Comparison of MFEC/MFES and packed bed (PB) properties

 

Volume %

Weight %

 

MFEC/MFES

PB

MFEC/MFES

PB

Fibers

2-8

-

37-100

-

Particles

0-35

60-70

0-63

100

Void

62-98

30-40

0

0


Where should they be used?

MFECs and MFESs are very suitable for process intensification, unit/process miniaturization, and portable applications. This technology is already widely used for air filtration, carbon monoxide catalytic filtration, deep desulfurization, Fischer-Tropsch synthesis, and methanol synthesis with many other heterogeneous reactions and processes currently under investigation.

How are MFECs and MFESs made?

Microfibrous entrapped catalysts and microfibrous entrapped sorbents are prepared using specialized wet-lay-roll-to-roll manufacturing techniques developed by IntraMicron and Auburn University. Most recently, microfibrous entrapment techniques have been advanced to the point that microfibrous media can entrap most pre-manufactured catalysts or sorbents of the right size specifications without contamination.