Systems and methods conducive to the formation of one or more alkene hydrocarbons using a methane source and an oxidant in an oxidative coupling of methane (OCM) reaction are provided. One or more vessels each containing one or more catalyst beds containing one or more catalysts each having similar or differing chemical composition or physical form may be used. The one or more catalyst beds may be operated under a variety of conditions. At least a portion of the catalyst beds may be operated under substantially adiabatic conditions. At least a portion of the catalyst beds may be operated under substantially isothermal conditions.

A fuel cell system and method, the system including a hotbox, a fuel cell stack disposed in the hotbox, an anode tail gas oxidizer (ATO) disposed in the hotbox, and a fuel exhaust processor fluidly connected to the hotbox. The fuel exhaust processor includes a first hydrogen pump configured to extract hydrogen from the anode exhaust received from the fuel cell stack and to output the hydrogen to a first hydrogen stream provided to the fuel cell stack, a second hydrogen pump configured to extract hydrogen from anode exhaust output from the first hydrogen pump and to output the hydrogen to the first hydrogen stream, and a third hydrogen pump configured to extract hydrogen from anode exhaust output from the second hydrogen pump and to output the hydrogen to a second hydrogen stream provided to the ATO.

A fixed bed reactor based on the principle of thermoluminescence to achieve in-situ heat removal and in-situ temperature measurement for strong exothermic reactions can monitor the temperature and heat of the exothermic reaction process from multiple angles, enhance the heat transfer of the catalytic bed layer, and effectively reduce or eliminate the hot spots generated by the exothermic reaction process. This reactor includes a fixed bed reaction tube, and the top of the fixed bed reaction tube is equipped with a xenon lamp pretreatment system, an optical signal detection system, and an infrared temperature measurement system.