Processes, systems, and apparatus are provided for producing a compressed process gas comprising light olefin such as ethylene. The process utilizes a pyrolysis reactor to produce the process gas. A power generator utilizes a turbine operated based on an Allam cycle to produce shaft power for operating one or more compressors involved in processing of the process gas while producing a reduced or minimized amount of CO.sub.2 that is released as a low-pressure gas phase product. Examples of using the shaft power for processing of the process gas can include compressing the process gas a process gas compressor powered by the produced shaft power and cooling the process gas using a refrigeration compressor powered by the produced shaft power.

A power generation system includes a combustion system, a turbocharger, and a heat recovery system. The combustion system is configured to combust a fuel with a flow of air. The combustion system is further configured to generate an exhaust stream. The turbocharger is configured to compress a flow of compressed air and to channel the flow of compressed air to the combustion system. The combustion system is configured to combust the fuel with the flow of compressed air and an additional flow of air. The heat recovery system is configured to recover heat from the exhaust stream and to drive the turbocharger. The heat recovery system uses a supercritical working fluid to absorb heat from the exhaust stream and to drive the turbocharger.

A power generation system includes a combustion system, a turbocharger, and a heat recovery system. The combustion system is configured to combust a fuel with a flow of air. The combustion system is further configured to generate an exhaust stream. The turbocharger is configured to compress a flow of compressed air and to channel the flow of compressed air to the combustion system. The combustion system is configured to combust the fuel with the flow of compressed air and an additional flow of air. The heat recovery system is configured to recover heat from the exhaust stream and to drive the turbocharger. The heat recovery system uses a supercritical working fluid to absorb heat from the exhaust stream and to drive the turbocharger.