Performance analysis of ocean thermal energy conversion system integrated with waste heat recovery from offshore oil and gas platform

• Published in: Case studies in thermal engineering Vol. 54; p. 104027
• Main Authors: Du, Yanlian, Peng, Hao, Xu, Jiahua, Tian, Zhen, Zhang, Yuan, Han, Xuanhe, Shen, Yijun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2024; Elsevier
• Subjects: Flue gas; Ocean thermal energy conversion; Production water; Thermodynamic performance; Waste heat recovery; Production water; Waste heat recovery; Flue gas; Ocean thermal energy conversion; Thermodynamic performance
• ISSN: 2214-157X; 2214-157X
• DOI: 10.1016/j.csite.2024.104027

To improve ocean thermal energy conversion (OTEC) system efficiency, four systems utilizing the waste heat recovery from offshore oil and gas platform are proposed, including flue gas boosting OTEC (system I), production water boosting surface seawater OTEC (system II), production water boosting working medium OTEC (system III), and production water boosting vapor OTEC (system IV). The system thermodynamic performance are investigated. The results show that system IV has larger power generation (Wnet), thermal efficiency (ηth) and exergy efficiency (ηex) than others. Compared with single OTEC system, for system IV, Wnet, ηth and ηex are increased by 1569.13 %, 70.35 % and 138.26 %, respectively. For system IV, with the increase of flue gas waste heat quantity from 2000 to 4000 kW, Wnet, ηth and ηex are increased by 562 %, 390 % and 181 % respectively; with the increase of production water waste heat quantity from 0 to 100 kW, Wnet, ηth and ηex are 12.59 %, 5.73 % and 2.86 % respectively. Wnet rises first and then decreases with the increase of evaporation pressure (Peva) or base fluid concentration (xb), presenting an optimal Peva of 1.5 MPa and xb of 0.82 corresponding to the maximum Wnet; Wnet decreases with the increase of condensation temperature. •Waste heat from offshore oil and gas platform is used to improve OTEC efficiency.•Four systems are designed to utilize flue gas and production water waste heat.•Thermodynamic model for predicting the novel system performance is established.•Power generation, thermal efficiency and exergy efficiency are increased.