Exergy analysis of the oil and gas processing on a North Sea oil platform a real production day

We explore the applicability of exergy analysis as an evaluation and monitoring tool for the oil and gas processing on an offshore platform. A real production day on a particular North Sea platform is analysed. A process flowsheet is simulated using measured process data. We distinguish between temperature based exergy, pressure based exergy and the mixing part of the chemical exergy. It is shown that physical exergy in the material streams mainly is pressure based exergy, and most exergy destruction is related to decrease or increase in pressure. The sub-processes with most destructed exergy are the production manifold (4600 kW), the recompression train (4150 kW) and the reinjection trains (10,400 kW). At this platform 260 kW separation work is done, where a considerable part is done in the compression trains in addition to in the separation train. The specific power consumption is 179 ± 3 kWh/Sm3 and the exergetic efficiency is 0.13 ± 0.02. We propose measures to decrease exergy destruction, and that exergy analysis should be taken into regular use by the oil and gas industry. This study serve as a showcase on how to do an exact analysis of an existing offshore platform using measured process data.