THERMODYNAMIC ANALYSIS OF ELECTRIC POWER PRODUCTION TECHNOLOGIES IN COGENERATION SYSTEMS ON FPSO AIMING TO REDUCE CO2 EMISSIONS

Abstract

Oil platforms are complex structures used to host workers and equipment
needed in offshore exploration. This study focuses on the platform's heat
and electricity cogeneration plant, which supplies a process heat exchangers
net, and provides the necessary electricity for all the equipment used for the
process and worker's accommodation in the platform. The platform demand
with maximum load is 75 MW, which could be achieved using four gas
turbines (25 MW each), one of which is kept for backup purposes or using
six dual-fuel engines diesel/natural gas (15 MW each), one of which is also
kept for backup purposes. Therefore, the thermodynamic analysis was
performed - considering five specific demand points of the platform -
comparing the two traditional configurations (gas turbines and dual-fuel
engines diesel/natural gas) and a combined configuration. The combined
configuration is composed of three gas turbines and two dual-fuel engines
diesel/natural gas (one of the gas turbines kept for backup purposes). The
configurations presented respectively 35.5%, 48.4% and 42.6% at highest
overall efficiency; 611.34 g/kWh, 373.45 g/kWh, 472.74 g/kWh at lowest
CO2 emissions considering full attendance of electrical and thermal
demands. The configurations using only gas turbines and the combined
fully attended the thermal demand of the platform without using auxiliary
pieces of equipment. Therefore, it was possible to observe that the
combined configuration presented several advantages concerning isolated
systems, proving to be an excellent option for sustainable energy
generation, reducing emissions of polluting gases and greater flexibility of
its operation concerning to configuration only with turbines, and physical
occupation in relation to configuration only with engines.