Following the trend of energy efficiency, the Oil&Gas sector is looking continuously to sustainable solutions aimed to reduce carbon footprint while maintaining competitiveness. The market shows that a clever way for O&G field is the implementation of Organic Rankine Cycle technology, which turns waste-heat into useful power, with minimum impact on the existing facilities. An ORC unit can exploit waste heat from several sources. Different ORC applications within the O&G field were studied.

The study conducted evolved in two phases. The first one aimed to identify the most suitable waste heat sources unexploited in the O&G facilities. The second one explored the technical and economic analysis of different configurations, in order to understand the best ORC solution for this industrial sector (in terms of process parameters, equipment and layout).

A proved ORC application was in the Gas-compressor-stations along the pipelines where multiple gas-turbines operating in open-cycle are used as prime-movers for compressors. Although reliable and flexible, they waste a significant amount of energy that can be converted into useful power by means of an ORC system, a clear opportunity to boost the overall efficiency of the plant.

Other applications regarded the exploitation of hot streams in associated petroleum gas (APG) process carried-out within refineries. Due to its poor chemical composition, APG are typically burned via torches, thus wasted. ORC can exploit that energy to produce electricity by means of a flare-gas-boiler which heats up a vector fluid to feed the turbogenerator.

Beside those waste-heat streams, another potential form of energy was available in gas pressure-letdown stations, where lamination valves dissipate the potential energy contained in the pressurized gas. In this scenario, the Gas-expander technology (similar to ORC) can be a valuable alternative and a more efficient solution. It consists in a turbine through which the NG at high pressure, rather than being laminated, expands to produce work, thereafter converted into electricity by a generator.

This paper will present the above-mentioned solutions, employed both individually or combined.

Considering a large-scale application, the paper will show how the implementation of the ORC recovery systems represents other than a way to meet sustainability targets also a remarkable and profitable business for O&G companies. Furthermore, the Gas Expander technology represents a solution to improve the energy efficiency of NG transmission and distribution networks, as well as upstream and downstream facilities.

You can access this article if you purchase or spend a download.