TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Component: The fuel processor further includes:(A) combustion catalyst disposed the second inner annular space;(B) methanator cooling coil having a fuel/water inlet and a fuel/water outlet disposed in a downstream region of the shift/methanator reactor vessel;(C) shift cooling coil having a shift gas inlet in fluid communication with the fuel/water outlet and having a shift gas outlet disposed in an downstream region of the shift/ methanator reactor vessel; and(D) steam coil having a pre-reformed gas inlet and a pre-reformed gas outlet disposed within the combustion chamber.The pre-reformed gas inlet is in fluid communication with the shift gas outlet and the pre-reformed gas outlet is in fluid communication with an interior of the reformer reactor vessel. The reformer vessel wall(s) forms a reformed gas outlet in fluid communication with an interior of the shift/methanator reactor vessel. The shift/methanator reactor vessel comprises a shift region into which the shift catalyst (17) is disposed, and a methanation region into which methanation catalyst (18) is disposed. The shift catalyst disposed upstream of the methanation catalyst.The apparatus further includes castable refractory and a moldable ceramic insulating foam (12) disposed in the outer annular space and the first inner annular space; ceramic start-up burner adapted to fire into the combustion chamber; and air humidification section disposed within the apparatus proximate the flue gas outlet. The reformer catalyst is disposed within the reformer reactor vessel. The housing is cylindrical in shape. The shift/methanator reactor vessel is cylindrical in shape and coaxially aligned with the housing. The reformer reactor vessel is cylindrical in shape and coaxially aligned with the housing.    TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Condition: A flue gas exhausted from the fuel processor has a temperature of 300-600 degrees F. The reformer section effluent exits from the reformer section at a temperature of 500-1300 degrees F. The hydrogen-rich product gas exiting from the shift/methanator reactor vessel is at 200-600 degrees F.