First and second law analysis of CO2 offshore compression system

Hamilton Yair Ortiz Cuchivague¹; Waldyr Luiz Ribeiro Gallo¹

¹ Unicamp

doi:10.20906/CPS/COB-2015-1722

Resumo

The Oil & Gas floating production, storage and offloading platforms (FPSO) are associated with high-energy consumption and CO2 emissions, which are related to separation systems, hydrocarbons and water treatment, gas and water overflow injection in reservoirs for storage or secondary elevation, and utilities in general where combustion of fuels is required. This study presents the formulation and simulation to develop a first and second law analysis for a booster and main CO2 injection compression processes within a FPSO, in order to identify and quantify the irreversibilities of each equipment and propose alternatives to increase the overall exergy efficiency. The analysis is done for a theoretical CO2 mass flow of 55kg/s, handled by a four stage booster compression train driven by gas turbine, with compression ratio 62,7:1, and a main injection compression train driven by medium-voltage electrical motors, in turn powered by gas turbo-generator electric power outlet, and a compression ratio 1,4:1. Three different values of CO2 mole fraction were modeled. Compression systems are one of the most energy-intensive processes therefore the results of availability assessments contribute to improve them.

Palavras-chave: CO2 compression; Exergy; FPSO