Intensified catalytic reactors for Fischer-Tropsch synthesis and for reforming of renewable fuels to hydrogen and synthesis gas

Abstract

Hydrogen and synthesis gas are components of key importance in energy, petroleum refining and petrochemical processing applications. Conventional hydrogen and synthesis gas manufacturing techniques, steam reforming and autothermal reforming, respectively, depend on the conversion of natural gas within packed-bed reactors, which inherently have weak heat transport properties. The resulting loss in reactor efficiency is accompanied by the increased emissions of undesired species like carbon dioxide and nitrogen oxides, side products of natural gas conversion. Heat transfer along catalyst bed is also critical in Fischer-Tropsch synthesis, in which desired product distribution strongly depends on reactor temperature that should be strictly controlled. One strategy for improving heat transfer rates, reducing unwanted emissions and ensuring sustainability together is to use intensified reactors, the units having surface area-to-volume ratios much higher than those of conventional reactors, in the conversion of renewable fuels instead of natural gas. Intensified reactors also offer high product selectivity and reduced pressure drop at compact volumes. In this context, recent experimental and modeling studies addressing reforming of ethanol, bio-oil, glycerol, biodiesel, dimethyl ether and ethylene glycol, and conversion of synthesis gas via the Fischer-Tropsch route in microchannel, monolith and foam reactors are reviewed. Despite a number of technical challenges, catalysis of renewable fuels to hydrogen, synthesis gas and synthetic fuels in intensified reactors finds increasing use in energy-related applications due to inherent benefits such as high productivity, sustainability and reduced emissions.