A system in one embodiment includes a mixing module, an oxidation module, and a heat exchanger. The mixing module is configured to receive and mix a boil-off gas stream from a cryotank. The oxidation module is configured to receive the mixed stream, and to oxidize the boil-off gas in the mixed stream to produce an exhaust stream. The heat exchanger is configured to exchange heat between streams passing through a first passage configured to receive at least a portion of the exhaust stream, and a second passage configured to receive a fluid including the boil-off gas. The heat exchanger is configured to heat the fluid including the boil-off gas and cool the at least a portion of the exhaust stream. The fluid including the boil-off gas is heated by the heat exchanger upstream of the oxidation module.