A reactor uses catalyst blocks for conversion of light hydrocarbons to hydrogen and to liquid hydrocarbons. The catalyst blocks stacked on top of one another within the reactor facilitate conversion of the light hydrocarbons. Electric heaters can be arranged in a variety of orientations within the reactor to supply heat for the conversion reaction. Alternatively, the catalyst blocks can be located within reaction tubes within the reactor and heated by combustion of a fuel adjacent to the reaction tubes. When operated in a regeneration mode, coke that accumulates within the reactor is removed by oxidation.