The present disclosure relates to systems and methods wherein a dilute hydrocarbon stream can be oxidized to impart added energy to a power production system. The oxidation can be carried out without substantial combustion of the hydrocarbons. In this manner, dilute hydrocarbon streams that would otherwise be required to undergo costly separation processes can be efficiently utilized for improving the power production system and method. Such systems and methods particularly can utilize dilute hydrocarbon stream including a significant amount of carbon dioxide, such as may be produced in hydrocarbon recovery process, such as enhanced oil recovery or conventional hydrocarbon recovery processes.

The present disclosure relates to systems and methods wherein a dilute hydrocarbon stream can be oxidized to impart added energy to a power production system. The oxidation can be carried out without substantial combustion of the hydrocarbons. In this manner, dilute hydrocarbon streams that would otherwise be required to undergo costly separation processes can be efficiently utilized for improving the power production system and method. Such systems and methods particularly can utilize dilute hydrocarbon stream including a significant amount of carbon dioxide, such as may be produced in hydrocarbon recovery process, such as enhanced oil recovery or conventional hydrocarbon recovery processes.

Power is produced by operating first and second nested cycles utilising CO.sub.2 as working fluid without mixing of working fluid between the nested cycles. The first cycle comprises a semi-open loop operating under low pressure conditions in which CO.sub.2 is sub-critical. The second cycle comprises a closed loop operating under higher pressure conditions in which CO.sub.2 is supercritical. The first cycle operates in a Brayton cycle including oxycombustion of hydrocarbons, preferably LNG, in a combustion chamber under low pressure conditions, expansion for power production to provide a first power source, cooling in a recuperator, compression, reheating by counter-current passage via the recuperator, and return of working fluid heated by the recuperator back to the combustion chamber. Water and excess CO.sub.2 resulting from the oxycombustion step are separated from the first cycle. The first cycle serves as a source of heat for the second cycle by gas/gas heat exchange in a gas/gas heat exchanger which results in cooling of the products of combustion and circulating working fluid in the first cycle and heating of working fluid in the second cycle. The second cycle is operated in a Brayton cycle including heating of working fluid in the second cycle by the gas/gas heat exchanger, expansion for power generation to provide a second power source, cooling in two-stages by first and second recuperator steps, compression, reheating by counter-current passage via the first recuperator step, and return of working fluid heated by the first recuperator step back to the gas/gas heat exchanger. Working fluid in the first cycle following the compression step is heated by working fluid in the second cycle by counter-current passage via the second recuperator step.

Power is produced by operating first and second nested cycles utilising CO.sub.2 as working fluid without mixing of working fluid between the nested cycles. The first cycle comprises a semi-open loop operating under low pressure conditions in which CO.sub.2 is sub-critical. The second cycle comprises a closed loop operating under higher pressure conditions in which CO.sub.2 is supercritical. The first cycle operates in a Brayton cycle including oxycombustion of hydrocarbons, preferably LNG, in a combustion chamber under low pressure conditions, expansion for power production to provide a first power source, cooling in a recuperator, compression, reheating by counter-current passage via the recuperator, and return of working fluid heated by the recuperator back to the combustion chamber. Water and excess CO.sub.2 resulting from the oxycombustion step are separated from the first cycle. The first cycle serves as a source of heat for the second cycle by gas/gas heat exchange in a gas/gas heat exchanger which results in cooling of the products of combustion and circulating working fluid in the first cycle and heating of working fluid in the second cycle. The second cycle is operated in a Brayton cycle including heating of working fluid in the second cycle by the gas/gas heat exchanger, expansion for power generation to provide a second power source, cooling in two-stages by first and second recuperator steps, compression, reheating by counter-current passage via the first recuperator step, and return of working fluid heated by the first recuperator step back to the gas/gas heat exchanger. Working fluid in the first cycle following the compression step is heated by working fluid in the second cycle by counter-current passage via the second recuperator step.

A (micro) gas turbine arrangement includes a gas turbine device having a combustor system, a turbine driven by an exhaust gas stream of the combustor system, and a compressor for supplying the combustor system with a compressed oxidant stream, as well as a recuperator for transferring at least a portion of the thermal power of the exhaust gas stream of the turbine to the compressed oxidant stream. At least one bypass diverts at least a portion of the oxidant stream or the exhaust gas stream around at least one heat exchanger of the recuperator, and at least one control element for adjusting the flow through the at least one bypass, to be able to adapt the quantity of heat emitted by the gas turbine arrangement at the design point, and thus to be able to improve the efficiency of a power-heat cogeneration system having such a gas turbine arrangement.

A hybrid-electric propulsion system includes a gas turbine engine, an electric machine coupled to and rotatably driven by the gas turbine engine to produce AC electric power, an energy storage system, and a propulsion unit. The gas turbine engine includes a combustor and a recuperator that places an exhaust air flow that is downstream from the combustor in a heat exchange relationship with a compressed air flow that is upstream from the combustor to transfer thermal energy from the exhaust flow to the compressed flow. The propulsion unit includes a fan and an electric motor rotably coupled to the fan, the electric motor being driven by electric power from one of the electric machine or the energy storage system.

A hybrid-electric propulsion system includes a gas turbine engine, an electric machine coupled to and rotatably driven by the gas turbine engine to produce AC electric power, an energy storage system, and a propulsion unit. The gas turbine engine includes a combustor and a recuperator that places an exhaust air flow that is downstream from the combustor in a heat exchange relationship with a compressed air flow that is upstream from the combustor to transfer thermal energy from the exhaust flow to the compressed flow. The propulsion unit includes a fan and an electric motor rotably coupled to the fan, the electric motor being driven by electric power from one of the electric machine or the energy storage system.

A system for cooling a gas turbine with an exhaust gas provided by the gas turbine generally includes an exhaust gas recirculation system including an exhaust gas scrubber. The exhaust gas recirculation system is disposed downstream from the gas turbine and may receive at least a portion of the exhaust gas provided by the gas turbine. The system may also include a moisture separator located downstream from the exhaust gas recirculation system, and a cooling circuit configured to connect to one or more cooling circuit inlets. The one or more cooling circuit inlets may provide fluid communication between the cooling circuit and the gas turbine.

A system for cooling a gas turbine with an exhaust gas provided by the gas turbine generally includes an exhaust gas recirculation system including an exhaust gas scrubber. The exhaust gas recirculation system is disposed downstream from the gas turbine and may receive at least a portion of the exhaust gas provided by the gas turbine. The system may also include a moisture separator located downstream from the exhaust gas recirculation system, and a cooling circuit configured to connect to one or more cooling circuit inlets. The one or more cooling circuit inlets may provide fluid communication between the cooling circuit and the gas turbine.

A system and method for generating an exhaust syngas are disclosed. The system includes a mixing unit, a heat exchanger, and an engine. The mixing unit is configured to mix a hydrocarbon fuel, an oxidant, and water to generate a fuel mixture. The heat exchanger is coupled to the mixing unit and is configured to receive the fuel mixture from the mixing unit, evaporate the water by heating the fuel mixture using a hot fluid, and generate a heated fuel mixture. The engine is coupled to the heat exchanger and is configured to receive the heated fuel mixture from the heat exchanger and generate an exhaust syngas by partially combusting the heated fuel mixture.