Further, the most striking inherent safety feature of a microchemical reactor is the low reactant inventory, which eliminates the accumulation of flammable gases that are well into the explosion regime. Microchannels behave much like a flame arrester placed in conventional systems because the channel dimensions are designed to be equal to or smaller than the explosion quench diameter. Methane is selected as the initial target for demonstrating potential applications for microchemical reactors. The primary limitation with partial oxidation processes, as previously articulated, is the necessity to remove rapidly the copious quantities of heat generated from the exothermic reactions. Steam reforming, on the other hand, is highly endothermic and requires careful thermal integration to add enough heat to maintain fast reaction rates.
Microchemical reactors can address each limitation.
The other driving force for targeting methane is the interest by several DOE agencies in carbon management for mitigation of global warming and for hydrogen production at stationary power plants. Carbon dioxide is often formed as a byproduct during methane steam reforming, and many other commercial reactions. As federal emissions regulations for carbon dioxide are becoming increasingly stringent, options for the conversion of carbon dioxide to useful products are being investigated. Other Group VIII metals are highly active for methanation, and several options have been explored for using them as catalysts. A variety of oxide supports have been examined.