Transient N2O decomposition process and reactor

A catalytic N2O decomposition reactor for generating a heated effluent comprising oxygen, which comprises an inner and an outer annulus in flow communication and a reactor exit fitting in the inner annulus, wherein a N2O feed mixture introduced into the outer annulus passes into the inner annulus and the heated effluent leaves the reactor through the exit fitting in the inner annulus, wherein the inner annulus comprises a N2O decomposition catalyst, and wherein the N2O feed mixture is preheated to a selected temperature in the outer annulus prior to contacting the N2O decomposition catalyst in the inner annulus, wherein:

• a. at least a portion of the walls forming the outer annulus are ribbed, finned or wrapped with wire,
• b. the reactor further comprises a choke flow venturi valve at the exit fitting in the inner annulus to maintain pressure in the reactor and wherein the heated effluent containing oxygen exits the reactor through the choked flow venturi valve;
• and/or
• c. the reactor further comprises a flow controller for adjusting the CO2 content in the N2O feed mixture and at least one thermocouple for monitoring temperature of the heated effluent containing oxygen exiting the reactor.