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Comparison and analysis of two nitrogen expansion cycles for BOG Re-liquefaction systems for small LNG ships
- Source :
- Energy. 172:769-776
- Publication Year :
- 2019
- Publisher :
- Elsevier BV, 2019.
-
Abstract
- To maintain the pressure of cargo tank and to minimize natural gas loss, two nitrogen expansion cycles for boil-off gas (BOG) re-liquefaction systems, specifically designed for small LNG ships are proposed and optimized: 1) Case 1, re-liquefaction process with the parallel nitrogen expansion, 2) Case 2, re-liquefaction process with the serial nitrogen expansion. The simulation and analysis of the two processes are carried out by using Aspen HYSYS and the genetic algorithms are selected as the optimization method. It can be found that the specific energy consumption (SEC) of 0.7333 kWh/kgLNG, the coefficient of performance (COP) of 0.2538 and the figure of merit (FOM) of 0.2827 are achieved in Case 1 and the SEC of 0.7539 kWh/kgLNG, the COP of 0.2464 and the FOM of 0.2757 are achieved in Case 2 by comparing the two optimized cases. Moreover, the total exergy losses for Case 1 and Case 2 are 153.34 kW and 160.69 kW, respectively.
- Subjects :
- Exergy
020209 energy
chemistry.chemical_element
02 engineering and technology
Industrial and Manufacturing Engineering
020401 chemical engineering
Natural gas
Genetic algorithm
0202 electrical engineering, electronic engineering, information engineering
Figure of merit
0204 chemical engineering
Electrical and Electronic Engineering
Process engineering
Bog
Civil and Structural Engineering
geography
geography.geographical_feature_category
business.industry
Mechanical Engineering
Liquefaction
Building and Construction
Coefficient of performance
Pollution
Nitrogen
General Energy
chemistry
Environmental science
business
Subjects
Details
- ISSN :
- 03605442
- Volume :
- 172
- Database :
- OpenAIRE
- Journal :
- Energy
- Accession number :
- edsair.doi...........20953ac70352a772a619e6c896f01242