NOVELTY - A reformer has cylinder (6) with pelletized catalyst, fuel tube, steam tube coaxial with fuel tube, and outflow tube. The steam tube extends to outflow end of fuel tube to cause the steam to cross the fuel outflow at an acute angle from all directions. The hydrocarbon gas and steam are mixed before coming in contact with the catalyst to produce high yield of hydrogen.    USE - For mixture of low pressure hydrocarbon gas and steam to supply hydrogen as fuel for proton exchange fuel cell.    ADVANTAGE - The reformer produces hydrogen gas at a high yield by using an improved gaseous hydrocarbon fuel and steam delivery system comprising to coaxial tubes.    DETAILED DESCRIPTION - A reformer has    (1) cylinder loosely packed with a pelletized catalyst with a cap at each end;    (2) fuel tube for introducing a low pressure hydrocarbon gas into the cylinder, having an outflow end coupled to the cylinder through a cap at one end of the cylinder;    (3) steam tube coaxial with the fuel tube and surrounds the fuel tube for introducing steam and a pressure higher than the hydrocarbon gas through the cap; and    (4) outflow tube protruding outwardly from the cylinder through an end cap at the end of the cylinder.    The steam tube has a tip of finite length at its outflow end that is gradually reduced in diameter over its length to form a truncated conical tip, with its open end of smaller diameter than the steam tube diameter forming an outflow end for fuel tube.    The steam tube extends to the outflow end of the fuel tube not only for flowing steam to draw out the hydrocarbon gas, but also flows through a core of fuel outflow in a direction which is at an acute angle with the direction of fuel outflow port, which is substantially along the axis of coaxial fuel and steam tubes, thereby causing the steam to cross the fuel outflow at an acute angle from all radial directions. The hydrocarbon gas and steam are mixed before contacting the catalyst, as the steam and fuel mixture flows over the catalyst to produce high yield of hydrogen by converting the hydrocarbon gas into hydrogen, carbon monoxide and carbon dioxide.    DESCRIPTION OF DRAWING(S) - The figure shows the block diagram of fuel cell system utilizing the reformer.    Cylinder (6)    Heat source (7)