A chemical reactor is provided that includes: a plurality of tubes having a catalytic reactor substrate therein, each of the tubes having an inlet at one end for receiving a fluid flow and an outlet at an opposing end for discharging fluid flow, and a longitudinal axis parallel to the direction of fluid flow through the tube, the longitudinal axis of each tube being parallel to one another; and a plurality of heat exchange fins disposed on and extending radially from the exterior surface of each tube; the heat exchange fins on each tube independently having a profile along a cross-section perpendicular to the longitudinal axis of each tube, and the tubes being arranged with respect to one another, such that the heat exchange fin profiles together form a tessellated pattern in a plane that is perpendicular to the longitudinal axes of the tubes.