TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Apparatus: The coolant fluid conduit (which is a heat exchange element with internal cooling) is sandwiched between a pair of monolithic open cell foam components (made of brazing material) (MOCFCs) which are brazed to each coolant fluid conduit. The MOCFCs are sandwiched between, and brazed to plates (40,42) which define outer margins of heat exchange assembly. A fuel gas flow structure directs fuel gas from flow section (I) of fuel gas and oxygen to heat exchange section (I), so that the temperature of fuel gas and oxygen mixture is controlled in the assembly. The coolant fluid conduit extends through flow section (I) which also includes a catalyzed MOCFC. The plate (I) is interposed between the flow section (I) and heat exchange section (I). Plates (II) and (III) are provided on the sides of flow section (I) of fuel gas and oxygen, and heat exchange section (I). The coolant fluid conduit is passed through all the plates to provide coolant fluid to both flow section (I) and heat exchange section (I). The lattice of MOCFC in flow section (I) of fuel gas and oxygen, is provided with a wash coat on which a suitable catalyst is deposited. A catalyzed flow section (II) of fuel gas and oxygen is connected to the heat exchange section (I) and is operable to receive the mixture of fuel gas and oxygen from the heat exchange section (I). Heat exchange section (II) connected to the catalyzed fuel gas and oxygen flow section (II), receives the fuel gas and oxygen mixture from flow section (II). Metal plates are also interposed between each flow sections (I and II) from adjacent heat exchange sections. The coolant fluid conduit extends through all MOCFCs and parallel to all the plates. The mixture of fuel gas and oxygen flows through an assembly in a direction perpendicular to the flow direction of coolant fluid. The coolant fluid enters the assembly through heat exchange section (II) and exits through flow section (I). Preferred Condition: Catalyst beds (I and II) are operated at 104-177 degrees C and 77-116 degrees C, respectively. Heat exchange sections (I and II) are operated at 77-177 degrees C and 77-116 degrees C, respectively.