Comparative assessment of advanced power generation and carbon sequestration plants on offshore petroleum platforms

On conventional offshore petroleum platforms, the combined heat and power production (CHP) currently depends on simple cycle gas turbine systems (SCGT) that operate at lower efficiency and increased environmental impact compared to modern onshore thermoelectric plants. Additionally, the reduced space and the limited weight budget on offshore platforms have discouraged operators from integrating more efficient, but also bulkier cogeneration cycles (e.g. combined cycles). In spite of these circumstances, more stringent environmental regulations of offshore oil and gas activities have progressively led to a renewed interest in the integration of advanced cogeneration systems, together with either customary or unconventional carbon capture approaches, to maintain both higher power generation efficiencies and reduced CO₂ emissions. Thus, in this paper, it is evidenced how advanced gas turbine concepts are promising technologies for maintaining or even increasing efficiency, while facilitating the capture rate of CO₂ produced, either for geological storage or enhanced oil recovery. Despite the profuse research works on onshore applications, advanced cogeneration and carbon capture systems have been barely studied in the context of supplying power to offshore petroleum platforms. Accordingly, the performance of a conventional offshore petroleum production platform (without carbon capture system) is compared to other configurations, based on either an amine-based chemical absorption system or oxyfuel combustion concepts (S-Graz and Allam cycles) for CO₂ capture purposes. Since the original power and heat requirements of the processing platform must remain satisfied, an energy integration analysis is performed to determine the waste heat recovery opportunities. Additionally, the exergy method helps quantifying the most critical components that lead to the largest irreversibility and identifying the thermodynamic potential for enhanced cogeneration plants. As a result, oxyfuel equipped platforms provide a diversified set of advantages, while keeping competitive efficiencies. For instance, advanced systems allow for cutting down ostensibly the atmospheric CO₂ emissions compared to the conventional and amine-based power plant configurations of the FPSO.