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. 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.