Technologies for waste heat recovery in off-shore applications

Leonardo Pierobon, Fredrik Haglind, Rambabu Kandepu, Alessandro Fermi, Nicola Rossetti

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

Abstract

In off-shore oil and gas platforms the selection of the gas turbine to support the electrical and mechanical demand on site is often a compromise between reliability, efficiency, compactness, low weight and fuel flexibility. Therefore, recovering the waste heat in off-shore platforms presents both technological and economic challenges that need to be overcome. However, onshore established technologies such as the steam Rankine cycle, the air bottoming cycle and the organic Rankine cycle can be tailored to recover the exhaust heat off-shore. In the present paper, benefits and challenges of these three different technologies are presented, considering the Draugen platform in the North Sea as a base case. The Turboden 65-HRS unit is considered as representative of the organic Rankine cycle technology. Air bottoming cycles are analyzed and optimal design pressure ratios are selected. We also study a one pressure level steam Rankine cycle employing the once-through heat recovery steam generator without bypass stack. We compare the three technologies considering the combined cycle thermal efficiency, the weight, the net present value, the profitability index and payback time. Both incomes related to CO2 taxes and natural gas savings are considered. The results indicate that the Turboden 65-HRS unit is the optimal technology, resulting in a combined cycle thermal efficiency of 41.5% and a net present value of around 15 M$, corresponding to a payback time of approximately 4.5 years. The total weight of the unit is expected to be around 250 ton. The air bottoming cycle without intercooling is also a possible alternative due to its low weight (76 ton) and low investment cost (8.8 M$). However, cycle performance and profitability index are poorer, 12.1% and 0.75. Furthermore, the results suggest that the once-trough single pressure steam cycle has a combined cycle thermal efficiency of 40.8% and net present value of 13.5 M$. The total weight of the steam Rankine cycle is estimated to be around 170 ton.
Original languageEnglish
Title of host publicationProceedings of the ASME 2013 International Mechanical Engineering Congress & Exposition (IMECE 2013)
Number of pages10
PublisherAmerican Society of Mechanical Engineers
Publication date2013
PagesIMECE2013-62304
Publication statusPublished - 2013
EventASME 2013 International Mechanical Engineering Congress & Exposition - San Diego, CA, United States
Duration: 13 Nov 201321 Nov 2013

Conference

ConferenceASME 2013 International Mechanical Engineering Congress & Exposition
CountryUnited States
CitySan Diego, CA
Period13/11/201321/11/2013

Cite this

Pierobon, L., Haglind, F., Kandepu, R., Fermi, A., & Rossetti, N. (2013). Technologies for waste heat recovery in off-shore applications. In Proceedings of the ASME 2013 International Mechanical Engineering Congress & Exposition (IMECE 2013) (pp. IMECE2013-62304). American Society of Mechanical Engineers.