Method and apparatus for steam reforming

A method and apparatus are disclosed for performing a steam reforming reaction. A heat source (10) is provided to supply heat to a surrounding reaction chamber (21) in which the steam reforming reaction takes place in the presence of a steam reforming catalyst (20). The heat source (10) advantageously generates heat by the catalytic combustion of fuel so that the heat source does not have to operate at the higher temperatures of conventional steam reforming reactors. The heat source catalyst (11) may be provided as a coating on the inside of a tube arranged to receive a combustion mixture. The combustion mixture may be delivered to the heat source through a perforated tube (12) arranged with more perforations (13) at one end to vary the amount of heat delivered to the reaction chamber (21) along its length. The reaction chamber may be surrounded by a hydrogen selective membrane (30) to enable hydrogen produced in the steam reforming reaction to leave the reaction chamber. The steam reforming catalyst (20) is preferably removable from the reaction chamber to enable replacement when it's activity has fallen to an unacceptable level