Microchannel reactors with temperature control

A method for performing an equilibrium limited exothermic chemical process comprising:

• performing an equilibrium limited exothermic chemical process by flowing reactants through a reaction microchamber in thermal contact with at least one heat exchange channel, and
• conducting heat generated by the equilibrium limited exothermic chemical process into fluid flowing through the at least one heat exchange channel in sufficient quantity to lower the temperature of the reactants as they progress through the reaction microchamber by at least about 25° C. and to substantially increase at least one performance value of the exothermic chemical process relative to its equilibrium value under isothermal conditions at the highest temperature of the reactants in the reaction microchamber.

A method for performing a reversible exothermic reaction comprising:

• flowing reactants for a reversible exothermic reaction through a reaction microchamber having an inlet end and an outlet end, wherein the reaction microchamber is in thermal contact with an inlet portion and an outlet portion of a heat exchange channel, and
• transferring heat generated by the exothermic reaction into fluid flowing through the heat exchange channel in sufficient quantity such that the temperature of the heat exchange fluid in the outlet portion of the heat exchange channel is not more than about 25° C. colder than the temperature of the reactants at the inlet end of the reaction microchamber and the outlet end of the reaction microchamber is substantially cooler than the inlet end of the reaction microchamber.

A method for performing a water gas shift reaction on the product of a fuel reforming process comprising:

• providing a reaction mixture containing CO, CO2, H2O and H2 into a reaction microchamber wherein the reaction microchamber is in thermal contact with at least one heat exchange channel through an intermediate wall portion and the volume of the reaction microchamber, the adjacent portion of the at least one heat exchange channel, and the intermediate wall portion define a heat exchange core volume;
• and
• catalytically converting CO to CO2 in the reaction microchamber at a rate of at least about 50 mmol per hour per cm3 of heat exchange core volume and transferring heat out of the reaction microchamber such that the fluid exiting the reaction microchamber contains less than 2% CO by mole and is substantially colder than the fluid entering the reaction microchamber.

A method for performing a water gas shift reaction comprising:

• providing a reaction mixture comprising the outlet of a fuel reforming process and containing CO, CO2, H2O and H2 into a reaction microchamber wherein the reaction microchamber is in thermal contact with at least one heat exchange channel through an intermediate wall portion and the volume of the reaction microchamber, the adjacent portion of the at least one heat exchange channel, and the intermediate wall portion define a heat exchange core volume;
• and
• catalytically converting CO to CO2 in the reaction microchamber and transferring heat generated by the reaction to heat exchange fluid flowing through the heat exchange channel at a heat transfer rate of greater than about 0.5 W/cm3 of heat exchange core volume such that the approach temperature is less than 50° C.

A method for performing an endothermic and a reversible exothermic reaction comprising:

• flowing endothermic reactants through an endothermic reaction microchamber in thermal contact with an exothermic reaction microchamber to transfer heat from the exothermic reaction to the endothermic reaction to sustain the endothermic reaction, wherein heat is transferred in sufficient quantity to substantially raise the temperature of the endothermic reactants as they travel through the endothermic reaction microchamber.

A method for performing a reversible chemical reaction comprising flowing reactants through a reaction microchannel in thermal contact with a heat exchange channel, reacting the products in the reaction microchannel, and conducting heat between the reaction microchannel and fluid flowing through the heat exchange channel during the reaction, wherein reactants contact reaction catalyst of substantially non-uniform catalyst activity along the length of the reaction microchannel.

A device comprising:

• a reaction microchamber having a first and second end and including a catalyst material in the form of a planar porous sheet, the reaction microchamber further including and at least a first flow path on one side of the sheet in fluid communication with a reactor inlet and at least a second flow path on an opposing sides of the sheet in fluid communication with a reactor outlet wherein a substantial portion of mass transport between the reactor inlet and the reactor outlet occurs through the sheet;
• at least one heat exchange microchannel in thermal contact with the reaction microchamber;
• wherein the first and second ends of the reaction microchamber are at substantially different temperatures.