A process and system for a process for releasing hydrogen from a hydrogenated organic carrier. The process including providing a reactor system comprising a first reaction zone and a second reaction zone, the first reaction zone having a first reaction condition and the second reaction zone having a second reaction condition, wherein the first reaction condition and the second reaction condition are different. A ballast system and method are also disclosed. The ballast system includes at least one vessel containing metal hydride capable of selectively storing hydrogen from the hydrogen-containing stream and one or both of selectively providing hydrogen to one or both of a hydrogen load or the dehydrogenation system.