scholarly journals Rollover of Liquid Natural Gas in a Storage Tank: A Numerical Simulation

2021 ◽  
Author(s):  
Yinbin Lu ◽  
Chenwei Liang
Keyword(s):  
Natural Gas ◽  
Storage Tank ◽  
Initial Density ◽  
Critical Density ◽  
Liquefied Natural Gas ◽  
Density Difference ◽  
Storage Tanks ◽  
Exponential Functions ◽  
Double Exponential ◽  
Liquid Natural Gas

In the filling and transportation processes of liquefied natural gas (LNG), the safety of LNG storage tanks is compromised because of rollover phenomenon. As such, the rollover factors of LNG in a storage tank should be identified to prevent or weaken the rollover intensity of LNG. In this study, the rollover behavior of LNG in a storage tank is numerically simulated. The density of the two layers in a LNG storage tank is related to temperature in our numerical model. It is found that the greater the significant initial density difference (range of 1-12 kg·m-3) is, the more obvious the LNG rollover will be. A density difference of 7.5 kg·m-3 is found as the critical density difference in the present work. When the initial density difference exceeds the critical density difference, the LNG rollover coefficients increase dramatically. Moreover, an LNG rollover model with two daughter models is proposed, which are divided by the critical initial density difference, i.e., a cubic relationship between rollover coefficients and the initial density difference when the density difference is less than 7.5 kg·m-3 and secondly, a linear relationship between the rollover coefficient and the double exponential functions when the density difference is larger than 7.5 kg·m-3.

Oil and Gas Storage Tank Risk Analysis

2014 ◽  
pp. 303-321
Author(s):  
Katarina Simon
Keyword(s):  
Natural Gas ◽  
Storage Tank ◽  
Oil And Gas ◽  
Gas Storage ◽  
Liquefied Natural Gas ◽  
Oil Refinery ◽  
Storage Tanks ◽  
Gaseous State ◽  
The Subject ◽  
Salt Caverns

Storage tanks are widely used in the oil refinery and petrochemical industry in storing a multitude of different products ranging from gases, liquids, solids, and mixtures. Design and safety concerns have become a priority due to tank failures causing environment pollution as well as fires and explosions, which can result in injuries and fatalities. The chapter illustrates different types of crude oil and oil product storage tanks as well as the risks regarding the storage itself. Considering that the natural gas, in its gaseous state, is stored in underground storages like oil and gas depleted reservoirs, aquifers or salt caverns, and there are numerous publications and books covering the subject in detail, this chapter only illustrates the storage of liquefied natural gas and the risks posed by its storage.

Oil and Gas Storage Tank Risk Analysis

2015 ◽  
pp. 128-142
Author(s):  
Katarina Simon
Keyword(s):  
Natural Gas ◽  
Storage Tank ◽  
Oil And Gas ◽  
Gas Storage ◽  
Liquefied Natural Gas ◽  
Oil Refinery ◽  
Storage Tanks ◽  
Gaseous State ◽  
The Subject ◽  
Salt Caverns

Storage tanks are widely used in the oil refinery and petrochemical industry in storing a multitude of different products ranging from gases, liquids, solids, and mixtures. Design and safety concerns have become a priority due to tank failures causing environment pollution as well as fires and explosions, which can result in injuries and fatalities. The chapter illustrates different types of crude oil and oil product storage tanks as well as the risks regarding the storage itself. Considering that the natural gas, in its gaseous state, is stored in underground storages like oil and gas depleted reservoirs, aquifers or salt caverns, and there are numerous publications and books covering the subject in detail, this chapter only illustrates the storage of liquefied natural gas and the risks posed by its storage.

scholarly journals Evolution Process of Liquefied Natural Gas from Stratification to Rollover in Tanks of Coastal Engineering with the Influence of Baffle Structure

2021 ◽  
Vol 9 (1) ◽  
pp. 95
Author(s):  
Zhe Wang ◽  
Fenghui Han ◽  
Yuxiang Liu ◽  
Wenhua Li
Keyword(s):  
Natural Gas ◽  
Storage Tank ◽  
Liquefied Natural Gas ◽  
Coastal Engineering ◽  
Density Difference ◽  
Evolution Process ◽  
Heat Leakage ◽  
Safety Risks ◽  
Boundary Velocity ◽  
Inducing Factors

During the storage process, liquefied natural gas (LNG) may undergo severe evaporation, stratification, and rollover in large storage tanks due to heat leakage, aging, or charging, causing major safety risks. Therefore, this article theoretically analyzes the causes and inducing factors of the LNG stratification and rollover phenomenon in the storage tank of coastal engineering. The computational fluid dynamics was used to establish a numerical model for the heat and mass transfer of LNG multicomponent materials in the imaginary layered interface of the storage tank, and the evolution process of LNG from spontaneous stratification to rollover was simulated. The accuracy of the mathematical model is verified by comparing numerical results with experimental data from open literature. The effects of the density difference between upper and lower layers, layering parameters, heat leakage parameters, and the baffles structure on the rollover process were studied. The effects of the interfacial surface variations are not included in this study. The results show that different baffle structures will form different boundary velocity fields, which will only affect the severity of the rollover, not the occurrence time. The larger the layering density difference, the earlier the rollover occurs. Under current conditions, the baffle structure that has the best suppression of rollover and the minimum boundary velocity is at 0.5 m above the stratified interface with the installation of the baffle at 5 degrees.

Numerical study of steady natural convection in a liquefied natural gas cylindrical storage tank equipped with baffles

2019 ◽  
Vol 234 (5) ◽  
pp. 709-721 ◽  
Author(s):  
Mohamed Haddar ◽  
Moez Hammami ◽  
Mounir Baccar
Keyword(s):  
Rayleigh Number ◽  
Natural Gas ◽  
Lateral Surface ◽  
Storage Tank ◽  
Cooling System ◽  
Numerical Study ◽  
Gas Storage ◽  
Liquefied Natural Gas ◽  
Natural Gas Storage ◽  
Average Temperature

In this paper, a study of cooling system for a liquefied natural gas storage tank is conducted. Our objective is to remedy the heat ingress to the liquefied natural gas from the environment using baffles toward limiting temperature elevation in the tank, and then the Boil-off Gas (BOG) formation. A specific code based on the finite volume method is developed to supply a fine knowledge of the hydrodynamic and thermal liquefied natural gas characteristics in the cylindrical tank heated from bottom and lateral surfaces. The effect of the number, position and dimension of baffles, on the flow structure and thermal behavior, has been analyzed. According to our simulation results, the baffles should be placed at the top of tank nearby the lateral wall as the liquefied natural gas dimensionless average temperature can be reduced by 36%. The installation of four rectangular baffles, equally spaced around the perimeter of the tank, gives better homogenization of the temperature field and decreases the average temperature by about 44% in order to limit BOG formation. Finally, two correlations of the Nusselt number are established for the flat rectangular baffle plates and the lateral surface of the cylindrical liquefied natural gas storage tank as a function of the Rayleigh number, as well as the baffle number. Scaling of these correlations with the Rayleigh number gives exponents of 0.25 and 0.18 for lateral surface and baffle, respectively, which are in good agreement with literature.

scholarly journals Techno Economic Evaluation of Cold Energy from Malaysian Liquefied Natural Gas Regasification Terminals

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4475 ◽  
Author(s):  
Mohd Amin Abd Majid ◽  
Hamdan Haji Ya ◽  
Othman Mamat ◽  
Shuhaimi Mahadzir
Keyword(s):  
Natural Gas ◽  
Liquefied Natural Gas ◽  
Economic Feasibility ◽  
Rate Of Return ◽  
Internal Rate Of Return ◽  
Economic Study ◽  
Cold Energy ◽  
Set Up ◽  
Liquid Natural Gas ◽  
Project Life

In order to cater for increased demand for natural gas (NG) by the industry, Malaysia is required to import liquid natural gas (LNG). This is done through PETRONAS GAS Sdn Bhd. For LNG regasification, two regasification terminals have been set up, one in Sungai Udang Melaka (RGTSU) and another at Pengerang Johor (RGTPJ). RGTSU started operation in 2013 while RGTPJ began operation in 2017. The capacities of RGTSU and RGTPJ are 3.8 (500 mmscfd) and 3.5 (490 mmscfd) MTPA, respectively. RGTSU is an offshore plant and uses an intermediate-fluid-vaporization (IFV) process for regasification. RGTPJ is an onshore plant and employs open-rack vaporization (ORV). It is known that a substantial amount of cold energy is released during the regasification process. However, neither plant captures the cold energy released during regasification. This techno economic study serves to evaluate the technical and economic feasibility of the cold energy available during regasification. It was estimated that approximately 47,214 and 88,383 kWh of cold energy could be generated daily at RGTPJ and RGTSU, respectively, during regasification processes. Converting this energy into RTh at 70% thermal efficiency, and taking the commercial rate of 0.549 Sen per RTh, for the 20-year project life, an internal rate of return (IRR) of up to 33% and 17% was estimated for RGTPJ and for RGTSU, respectively.

Investigation of fatigue performance of low temperature alloys for liquefied natural gas storage tanks

2015 ◽  
Vol 229 (7) ◽  
pp. 1300-1314 ◽  
Author(s):  
Dong-Jin Oh ◽  
Jae-Myung Lee ◽  
Byeong-Jae Noh ◽  
Wha-Soo Kim ◽  
Ryuichi-Ando ◽  
...  
Keyword(s):  
Low Temperature ◽  
Natural Gas ◽  
Structural Integrity ◽  
Liquefied Natural Gas ◽  
Operating Conditions ◽  
Production Costs ◽  
Fatigue Performance ◽  
Nickel Steel ◽  
Storage Tanks ◽  
Operating Life

One of the most important issues associated with liquefied natural gas (LNG) storage tanks, such as LNG carrier cargo tanks and land LNG tanks, is their structural integrity. In order to ensure the operating life and safety of LNG storage tanks used under operating conditions such as thermal and cyclic loadings, the securing of safety evaluations for fatigue performance is considered to be of particular importance. There have been various efforts to reduce the production costs of LNG storage tanks, such as the optimum selection of materials and the development of new low temperature materials. This, the motivation of this study is to evaluate new material candidates for LNG storage tanks. This study begins with a comprehensive review of the characteristics of low temperature alloys such as SUS 304L, Invar, A5083 and 9% Ni steel that are widely used for LNG storage tanks. Then, the fatigue characteristics of a newly developed low temperature material, 7% nickel steel are investigated. Finally, the fatigue performance of 7% nickel steel is compared with that of 9% nickel steel.

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