Effects of cooling and heating sources properties and working fluid selection on cryogenic organic Rankine cycle for LNG cold energy utilization

2021 ◽  
Vol 247 ◽  
pp. 114706
Author(s):  
Tianbiao He ◽  
Huigang Ma ◽  
Jie Ma ◽  
Ning Mao ◽  
Zuming Liu
Keyword(s):  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Energy Utilization ◽  
Working Fluid ◽  
Cold Energy ◽  
Working Fluid Selection

scholarly journals Cold Energy Utilization in LNG Regasification System Using Organic Rankine Cycle and Trilateral Flash Cycle

2020 ◽  
Vol 64 (4) ◽  
pp. 342-349 ◽  
Author(s):  
Sindu Daniarta ◽  
Attila R. Imre
Keyword(s):  
Output Power ◽  
Organic Rankine Cycle ◽  
Thermodynamic Cycle ◽  
Rankine Cycle ◽  
Single Step ◽  
Energy Utilization ◽  
Working Fluid ◽  
Safety Issues ◽  
Cold Energy ◽  
Net Power Output

"Cold energy" refers to a potential to generate power by utilizing the exergy of cryogenic systems, like Liquefied Natural Gas (LNG), using it as the cold side of a thermodynamic cycle, while the hot side can be even on the ambient temperature. For this purpose, the cryogenic Organic Rankine Cycle (ORC) is one type of promising solution with comprehensive benefits to generate electricity. The performance of this cycle depends on the applied working fluid. This paper focuses on the applicability of some natural working fluids and analyzes their performance upon cold energy utilization in the LNG regasification system. An alternative method, the cryogenic Trilateral Flash Cycle (TFC), is also presented here. The selection of working fluid is a multi-step process; the first step uses thermodynamic criteria, while the second one is addressing environmental and safety issues. It will be shown that in LNG regasification systems, single cryogenic ORC performs higher net output power and net efficiency compared to single cryogenic TFC. Propane as working fluid in the single cryogenic ORC generates the highest net output power and net efficiency. It is demonstrated, that concerning 26 novel LNG terminals, a net power output around 320 MW could be recovered from the cold energy by installing a simple cycle, namely a single-step cryogenic ORC unit using propane as working fluid.

Optimization of Overcritical Organic Rankine Cycle

2016 ◽  
Vol 831 ◽  
pp. 306-315
Author(s):  
Qing Quan Wang ◽  
Sławomir Smoleń
Keyword(s):  
Numerical Method ◽  
Thermal Efficiency ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Independent Variables ◽  
Hot Temperature ◽  
Working Fluid Selection ◽  
Two Independent Variables

This paper explores the optimization cases for overcritical Organic Rankine Cycle (ORC) in various situations. First the ORC optimization in terms of working fluid selection is discussed. In this case, thermal efficiencies for 10 different working fluids have been calculated under certain temperature frames and the results are compared. Second, overcritical optimization case in terms of variation of hot temperature and evaporation pressure is presented. In this overcritical ORC case, the influence of evaporation pressure on ORC thermal efficiency is studied by conducting a case study of R234a, and first 1-D freedom optimization case is discussed within the variation of evaporation pressure. 2-D freedom optimization is also considered, in which the two independent variables, hot temperature and evaporation pressure, are both varied within certain boundaries. This study employs numerical method for this 2-D problem and it is also presented in detail in the case study.

scholarly journals Organic Rankine Cycle system performance targeting and design for multiple heat sources with simultaneous working fluid selection

2017 ◽  
Vol 142 ◽  
pp. 1950-1970 ◽  
Author(s):  
Mirko Z. Stijepovic ◽  
Athanasios I. Papadopoulos ◽  
Patrick Linke ◽  
Vladimir Stijepovic ◽  
Aleksandar S. Grujic ◽  
...  
Keyword(s):  
System Performance ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Heat Sources ◽  
Cycle System ◽  
Working Fluid Selection

Working Fluid and Parametric Optimization of a Two-Stage ORC Utilizing LNG Cold Energy and Low Grade Heat of Different Temperatures

2017 ◽  
Author(s):  
Zhixin Sun ◽  
Shujia Wang ◽  
Fuquan Xu ◽  
Tielong Wang
Keyword(s):  
Heat Source ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Cycle Performance ◽  
Maximum Efficiency ◽  
Working Fluid ◽  
Low Grade ◽  
Two Stage ◽  
Cold Energy ◽  
Low Grade Heat

Natural gas is considered as a green fuel due to its low environmental impact. LNG contains a large amount of cold exergy and must be regasified before further utilization. ORC (Organic Rankine Cycle) has been proven to be a promising solution for both low grade heat utilization and LNG cold exergy recovery. Due to the great temperature difference between the heat source and LNG, the efficiency of one-stage ORC is relatively small. Hence, some researchers move forward to a two-stage Rankine cycle. Working fluid plays a quite important role in the cycle performance. Working fluid selection of a two-stage ORC is much more challenging than that of a single-stage ORC. In this paper, a two-stage ORC is studied. Heat source temperatures of 100,150 and 200°C are investigated. 20 substances are selected as potential candidates for both the high and low Rankine cycles. The evaporating, condensing and turbine inlet temperatures of both Rankine cycles are optimized by PSO (Particle Swarm Optimization). The results show that the best combination for heat source temperature of 100°C is R161/R218 with the maximum exergy efficiency of 35.27%. The best combination for 150°C is R161/RC318 with the maximum efficiency of 37.84% and ammonia/ammonia with the maximum efficiency of 39.15% for 200°C. Fluids with intermediate critical temperature, lower triple point temperature and lower normal boiling temperature are good candidates.

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