Microfibrous Media Technology

Microfibrous media is a highly-porous, sintered, nonwoven support structure capable of entrapping catalysts, sorbents, and other desirable materials in a fixed-fluidized bed configuration. Microfibrous media can be made of polymers, ceramics, glasses, metals, and alloys by IntraMicron's proprietary wet-lay and sintering process. The material selected for the microfibrous matrix depends on the desired application. Polymers are typically used for low cost applications while ceramic/glass fibers are best for highly corrosive environments. Metal and alloy microfibers are ideal for cases where enhanced heat and/or electrical conductivity are desired. Sintering is a necessary step to stabilize the microfibrous structure by mechanically welding its component fibers. In the case of metal microfibrous media, this sintering step also puts the metal fibers in intimate thermal and electrical contact, enhancing the media's electrical and thermal properties.

Microfibrous Media Properties

Microfibrous media structures are unique because the volumetric loading of the metal fibers and the active phase are mostly independent of one another. This allows the relative amounts of each component to be adjusted over a wide range of parameters compared with most current materials.

Comparison of Microfibrous Media and packed bed (PB) properties

Volume % Weight %
Fibers 2-8 - 37-100 -
Particles 0-35 60-70 0-63 100
Void 62-98 30-40 0 0

When particles are included in the microfibrous media, they are much smaller than those typically used in packed bed systems. This allows mass transfer resistances to be significantly reduced or eliminated. The sintered microfibrous structure separates and supports the small particulates, allowing a high void fraction to be maintained to keep microfibrous media pressure drop low relative to a packed bed of similar particles. In addition to acting as a support structure, metal microfibrous media provides a heat and charge transfer network that enhances heat and/or electrical transfer between the catalyst particles. When Cu microfibrous media is used, effective thermal conductivities at least 50 times that of an alumina packed bed can be achieved with a 10-fold improvement in the inside-the-wall heat transfer coefficient.

MFM - PB Thermal Conductivity Comparison

Metal MFEC-alumina Packed Bed Thermal Conductivity Comparison

The versatility of the microfibrous media structure allows the heat and mass transport properties of the media to be varied by changing the intrabed voidage. This characterisic allows the microfibrous media structure to be tailored to give the optimal heat, mass, and charge transport characteristics for a numerous catalytic and sorptive processes. These improved characteristics result in microfibrous media-based systems having enhanced performance compared with traditional systems.