scholarly journals Organic Rankine Cycle for Recovery of Liquefied Natural Gas (LNG) Cold Energy

Author(s):  
Junjiang Bao
Brodogradnja ◽  
2021 ◽  
Vol 72 (4) ◽  
pp. 47-78
Author(s):  
Manuel Naveiro ◽  
◽  
Manuel Romero Gómez ◽  
Ignacio Arias Fernández ◽  
Javier Romero Gómez

This paper aims to review regasification technology installed in Floating Storage Regasification Units (FSRUs) and the potential offered by the exploitation of cold energy from liquefied natural gas (LNG) in these vessels. The assessment describes the main characteristics of regasification systems along with their respective advantages and limitations. Regasification systems in direct exchange (seawater and steam) and systems with intermediate fluids that use propane or water-glycol in the heat transfer process are studied. In recent years, water-glycol systems have cornered the market. The mixture, besides reducing the risk of freezing, is non-flammable, economical and highly available. Thermodynamic analysis of the regasification process shows that LNG cold energy is the main source of residual energy in these vessels; the specific energy and exergy content is more than double that of engine exhaust gases. Exploitation of this cold energy in power cycles could significantly reduce FSRUs harmful emissions and electrical energy could even be exported to shore. The organic Rankine cycle technology is the most well-known and widely studied, although scientific literature is scarce and there is a need to propose new regasification systems with cold energy exploitation that can be adopted on these vessels.


Energy ◽  
2013 ◽  
Vol 61 ◽  
pp. 179-195 ◽  
Author(s):  
In-Hwan Choi ◽  
Sangick Lee ◽  
Yutaek Seo ◽  
Daejun Chang

Author(s):  
M. A. Ancona ◽  
M. Bianchi ◽  
L. Branchini ◽  
A. De Pascale ◽  
F. Melino ◽  
...  

In the last years, the increased demand of the energy market has led to the increasing penetration of renewable energies in order to achieve the primary energy supply. However, natural gas is expected to still play a key role in the energy market, since its environmental impact is lower than other fossil fuels. It is mainly employed as gaseous fuel for stationary energy generation, but also as liquefied fuel, as an alternative to the diesel fuel, in vehicular applications. Liquefied Natural Gas is currently produced mainly in large plants directly located at the extraction sites and transported by ships or tracks to the final users. In order to avoid costs and environmental related impact, in previous studies Authors developed a new plant configuration for liquefied natural gas production directly at filling stations. One of the main issues of the process is that in various sections the working fluid needs to be cooled by external fluids (such as air for compressor inter and after-cooling or chilling fluids), in order to increase the global performances. As a consequence, an important amount of heat could be potentially recovered from this Liquefied Natural Gas production process. Thus, based on the obtained results, in this study the integration between the liquefaction process and an organic Rankine cycle is proposed. In fact, the heat recovered from the Liquefied Natural Gas production process can be used as hot source within the organic Rankine cycle. The aim of the work is the identification of the optimal integrated configuration, in order to maximize the heat recovery and, as a consequence, to optimize the process efficiency. With this purpose, in this study different configurations — in terms of considered organic fluid, architecture and origin of the recovered heat — have been defined and analyzed by means of a commercial software. This software is able to thermodynamically evaluate the proposed process and had allowed to define the optimal solution.


2019 ◽  
Vol 23 (6 Part B) ◽  
pp. 3865-3875
Author(s):  
Shouguang Yao ◽  
Likang Xu ◽  
Liang Tang

The topic of this study is the intermediate fluid vaporizer gasification system for a liquefied natural gas floating storage regasification unit. To reduce the loss of heat exchange, the primary distributary cascade three-level Rankine cycle is optimised based on the cascade three-level Rankine cycle that uses the cold energy of liquefied natural gas to generate power. The optimized primary distributary cascade three-level Rankine cycle is then compared with the original cascade three Rankine cycle established under the same conditions. Then, a secondary distributary cascade three-level Rankine cycle is proposed. Results show that under a liquefied natural gas flow of 175 t/h, the primary distributary cascade three-level Rankine cycle system exhibits a maximum net output power of 4130.72 kW and an exergy efficiency of 23.78%, which is higher than that of the typical cascade three-level Rankine cycle. Moreover, the net output power and exergy efficiency of the primary distributary cascade three-level Rankine cycle system increased by 3.71% and by 3.84%, respectively. The secondary distributary cascade three-level Rankine cycle system exhibits a maximum net output power of 4143.75 kW and an exergy efficiency of 23.85%.


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