Standardized Offshore Waste Heat Recovery Behind Industrial Gas Turbines

Abstract

Abstract This paper focuses on the benefits of utilizing waste heat recovery units (WHRUs) in offshore oil and gas applications. Today, a high number of offshore installations use gas turbines (GTs) for power generation and as mechanical drivers for critical equipment, such as compressors. Most installations, however, do not employ any form of waste heat recovery. This results in wasted energy and increased emissions, as hot exhaust gases from the GT are vented to the atmosphere. One of the factors that has contributed to the limited use of WHRUs on offshore facilities has to do with weight and space limitations. The paper discusses how original equipment manufacturers (OEMs) are addressing that challenge through both design standardization and modularization. For illustrative purposes, the paper discusses a line of standardized WHRUs which are designed for industrial and aeroderivative gas turbines in the 10–70 megawatt (MW) range. The WHRUs can be used for thermal fluids or applied as a drum-type steam generator (DTSG) or once-through steam generator (OTSG). Their vertical compact layout makes them particularly well suited for offshore installations, such as floating, production, storage, and offloading (FPSO) vessels, where weight and footprint of topsides modules are of particular importance. By standardizing the WHRU/DTSG/OTSG and leveraging a high degree of modularization, the units can be easily modified per project. Construction time can also be reduced by up to ~ 70% when compared to traditional horizontal gas turbine heat recovery designs. Standardization also enables a reduction in engineering efforts during project execution – resulting in increased product quality and lower CAPEX.