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Calculation and Analysis of Influencing Factors of Daily Evaporation Rate for Large LNG Storage Tank
Zhang Wenhao,
Tian Guansan,
Yin Xiao
Issue:
Volume 10, Issue 6, November 2021
Pages:
102-109
Received:
10 September 2021
Accepted:
2 November 2021
Published:
12 November 2021
Abstract: Because LNG has the advantages of high calorific value, low pollution and low price, this clean, high-quality fuel has attracted more and more attention from all walks of life. In recent years, LNG technology has developed rapidly, and the scale of installations has gradually increased, and a complete system project for LNG production and storage has been formed. The safe storage of LNG is vital to the development of the industry. The evaporation of LNG in the tank caused by the inflow of environmental heat is an important cause of overpressure and stratification and rollover in the tank, and affects the safe operation of the storage tank. Therefore, it is necessary to study the daily evaporation rate of the LNG storage tank and its influencing factors. Through the analysis of the cooling structure and heat exchange process of LNG storage tanks, a calculation method for heat leakage and daily evaporation rate of large LNG storage tanks is given, and the influence of solar radiation on the heat leakage of storage tanks is comprehensively considered. Taking a 30,000 cubic meter LNG storage tank as an example, the daily evaporation rate and influencing factors are calculated and analyzed. The results show that: (1) Daily evaporation rate of the LNG storage tank meets the relevant national design requirements. (2) The environmental temperature and full rate has a greater impact on the daily evaporation rate, and the environmental wind speed has a small impact on the daily evaporation rate. The calculation of the daily evaporation rate of the LNG storage tank and the analysis of influencing factors can provide a theoretical basis for the cold storage design and safe operation of the storage tank.
Abstract: Because LNG has the advantages of high calorific value, low pollution and low price, this clean, high-quality fuel has attracted more and more attention from all walks of life. In recent years, LNG technology has developed rapidly, and the scale of installations has gradually increased, and a complete system project for LNG production and storage h...
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Benzene-bridged Phenanthraquinone as Organic Cathode for Li-ion and Na-ion Batteries
Issue:
Volume 10, Issue 6, November 2021
Pages:
110-114
Received:
19 October 2021
Accepted:
5 November 2021
Published:
12 November 2021
Abstract: Organic electrode materials are widely applied for metal (lithium and sodium)-ion batteries (LIBs and SIBs) due to their structural diversity and redox reversibility. Molecule-aggregation organic electrodes in principle possess the “single-molecule-energy-storage” capability for metal-ion rechargeable batteries. Nevertheless, the small-molecule organic have serious solubility problems in traditional commercial electrolyte, which limited the application in rechargeable batteries. Besides dissolution issue, the effect of possible solvent co-intercalation in liquid electrolytes also devalues the true performance of organic electrodes due to the weak Van der Waals forces among organic molecules. Herein, an organic small-molecule cathode called benzene-bridged phenanthraquinone (BBP) with two phenanthraquinones are exploited as the highly stable organic cathode in LIBs and SIBs. Consequently, BBP can deliver high stale capacity above 67 and 57 mAh g-1 during a long cycle time in both batteries (500 mA g-1). In LIBs and SIBs, the resulting BBP can deliver a peak discharge capacity of 130 and 159 mAh g-1 cathode with an average voltage of 2.3 and 18 V. Meanwhile, the BBP can remain 79% and 88% capacity retention (133 and 126 mAh g-1) at 500 mA g-1 in LIBs and SIBs, respectively. And BBP delivers the capacities of 130 and 144 mAh g-1 for 50 cycles at 100 mA g-1 in LIBs and SIBs.
Abstract: Organic electrode materials are widely applied for metal (lithium and sodium)-ion batteries (LIBs and SIBs) due to their structural diversity and redox reversibility. Molecule-aggregation organic electrodes in principle possess the “single-molecule-energy-storage” capability for metal-ion rechargeable batteries. Nevertheless, the small-molecule org...
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State-of-charge Estimation of Lithium-ion Batteries Based on PSO-BP Neural Network
Biao Yang,
Yinshuang Wang,
Hao Gao
Issue:
Volume 10, Issue 6, November 2021
Pages:
115-120
Received:
25 October 2021
Accepted:
15 November 2021
Published:
17 November 2021
Abstract: The state of charge (SOC) of lithium-ion battery is a variable and cannot be measured directly by sensors. Therefore, accurate estimation of battery state of charge is the key to ensure the safe and reliable operation of battery management system (BMS) and reduce the required battery cost. In the research of estimating the state of charge of lithium-ion batteries, the initial setting of the weights and thresholds of the BP neural network easy to falls into the local minimum problem, which makes the SOC estimation insufficiently accurate. Therefore, a method of SOC estimation of lithium-ion battery based on particle swarm optimization (PSO) and BP neural network is proposed in this paper. Taking lithium manganese battery (LiMn2O4) as the object, use the multi-physics simulation platform COMSOL to conduct charging and discharging experiments on it, and collect the relevant performance parameters of the battery. Under the condition of constant temperature and constant current, the SOC of the battery is inferred according to the voltage and discharge rate. Building a PSO-BP neural network model with voltage and discharge rate as input and battery SOC as output. The performance of SOC estimation is evaluated from the aspects of overall correlation, training time and robustness. It is compared with the estimation method based on BP neural network. The simulation results show that the absolute error of the estimation method based on PSO-BP neural network is 2.68%, which is 3.18% higher than that of BP neural network, and the accuracy is higher. The proposed method has more advantages.
Abstract: The state of charge (SOC) of lithium-ion battery is a variable and cannot be measured directly by sensors. Therefore, accurate estimation of battery state of charge is the key to ensure the safe and reliable operation of battery management system (BMS) and reduce the required battery cost. In the research of estimating the state of charge of lithiu...
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Study on the Decay Law of γ Energy Spectrum of Radon and Its Daughters in Radon Chamber
Jiang Yunrui,
Lai Wanchang,
Liu Guanhua,
Lin Hongjian,
Sun Tao,
Zhai Juan
Issue:
Volume 10, Issue 6, November 2021
Pages:
121-125
Received:
28 October 2021
Accepted:
15 November 2021
Published:
17 November 2021
Abstract: Radon is one kind of radioactive gas which mainly distributed in soil and rocks, because of its strong upward migration ability, it is easy to diffuse into the air and cause radiation damage as the respiratory system enters the human body, which may cause lung cancer. Accurate measurement of concentration has always been a research area that has attracted much attention. There are various methods for measuring radon. Commonly used at home and abroad are thermoluminescence radon method, solid nuclear track radon method, activated carbon method, electret method, and scintillation chamber method. It is qualified for measurement under normal conditions, but in special applications such as the deduction of radon background in aerial gamma measurement, the above method is no longer applicable. At present, the detectors used in aviation gamma instruments at home and abroad are mainly large crystal sodium iodide detectors. The high-resolution array detector aviation gamma spectrometer developed by Ge Liangquan of Chengdu University of Technology also uses this kind of detection. In order to explore the effect of the detector on the direct measurement of the gamma energy spectrum of radon and its daughters. An experimental platform was built based on the HD-6 multifunctional automatic control radon chamber, the large crystal NaI(Tl) detector was used for measurement, and the HPGe detector was used for comparative measurement. Finally, the measurement results of the two were measured with the RAD7 radon meter. The obtained radon concentration was compared, and the reason for the abnormal data was studied. Through experiments, the large crystal NaI(Tl) detector can be applied to the direct measurement of the γ energy spectrum of radon and its daughters, and its practical effect is better than that of the electric cooling HPGe detector. The experiment found that the temperature is The count rate of the large crystal NaI(Tl) detector cannot be ignored, and temperature correction is required.
Abstract: Radon is one kind of radioactive gas which mainly distributed in soil and rocks, because of its strong upward migration ability, it is easy to diffuse into the air and cause radiation damage as the respiratory system enters the human body, which may cause lung cancer. Accurate measurement of concentration has always been a research area that has at...
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Fast Analysis of Mn, Co, and Ni in the Ternary Cathode Material Mixture of Lithium Battery with EDXRF
Shi Jie,
Lai Wanchang,
Zhai Juan,
Zhou Jinge,
Shu Ziyao,
Wu Peiliang,
Dai Wei,
Gu Runqiu
Issue:
Volume 10, Issue 6, November 2021
Pages:
126-134
Received:
28 October 2021
Accepted:
16 November 2021
Published:
17 November 2021
Abstract: The content of Mn, Co, and Ni in the ternary cathode material mixture of lithium batteries directly affects the electrochemical performance of the electrode material. The rapid measurement of the content of Mn, Co, and Ni is of great significance to the production and process control of the ternary cathode material. In this paper, energy dispersive X-ray fluorescence analysis (EDXRF) was used to analyze the content of Mn, Co, and Ni in the ternary cathode material mixture of lithium batteries. When calculating the peak area, the branch ratio subtraction method is used to correct the interference of the Kβ peak of Co on the Kα peak of Ni. In the spectrum data processing, combining the advantages of the SNIP method and the polynomial fitting method to subtract the scattering background, the two methods are combined to process the measured spectrum lines, and good results have been achieved. In the matrix effect correction, by comparing the theoretical mass absorption coefficient and the experimental results, it is concluded that the Mn, Co, and Ni in the ternary cathode material mixture of the lithium battery are affected by the matrix effect, which is established by the multiple regression analysis in the empirical coefficient method. Mathematical model to correct the absorption enhancement effect of Mn, Co and Ni. The experimental results show that the average absolute error of Mn, Co, and Ni content in the ternary cathode material mixture of lithium battery using the empirical coefficient method is 0.09%, 0.02%, 0.04%, and the average relative error is 0.52%, 0.12%, 0.13%. Single sample analysis only needs 200s, which meets the requirements of fast, efficient and accurate analysis.
Abstract: The content of Mn, Co, and Ni in the ternary cathode material mixture of lithium batteries directly affects the electrochemical performance of the electrode material. The rapid measurement of the content of Mn, Co, and Ni is of great significance to the production and process control of the ternary cathode material. In this paper, energy dispersive...
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Evaluation Method of Voltage Sag Severity in Distribution Networks
Issue:
Volume 10, Issue 6, November 2021
Pages:
135-140
Received:
15 November 2021
Accepted:
3 December 2021
Published:
7 December 2021
Abstract: Recently voltage sags have gradually become one of the most important power quality problems with the large scale use of sensitive electrical equipment. Analysis of varied attributes causing voltage sags can not only guide the planning, equipment selection, operation and maintenance of power supply engineering, but also can provide a theoretical basis for effectively assessing the risks and severity of the power quality incidents. It is meaningful to combine the existing problems of technology and management level to get the assessment results of the voltage sags. In this paper, clustering analysis and evaluation method are proposed for multi-cause attributes that affect voltage sags. The calculation method of the voltage on the multiple fault location parameters in the power grid is derived. The evaluation method of the voltage sags considering the user’s tolerance level is given. The characteristic properties of causes are used as parameters to describe disturbances which provide a basis for voltage sag evaluation. Then the equipment compatibility index is introduced, the analytic hierarchy process is used to determine the weight of the voltage sag evaluation index, and the severity of the voltage sag of each node of the distribution network is calculated to realize the distribution network voltage sag severity assessment. Finally, the voltage sag under multi causal attributes is analyzed using the equipment compatibility index as the standard, and the sag severity of the equipment is analyzed. The multi-factor attributes contribution degree proposed in this paper takes the equipment compatibility as the index, and can accurately reflect the impact of various attributes on equipment after voltage sags.
Abstract: Recently voltage sags have gradually become one of the most important power quality problems with the large scale use of sensitive electrical equipment. Analysis of varied attributes causing voltage sags can not only guide the planning, equipment selection, operation and maintenance of power supply engineering, but also can provide a theoretical ba...
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A System Dynamics Modelling of a Long-term Residential Electricity Consumption in Lomé, Togo
Kokou Amega,
Yacouba Moumouni,
Yendoubé Lare
Issue:
Volume 10, Issue 6, November 2021
Pages:
141-150
Received:
18 November 2021
Accepted:
7 December 2021
Published:
24 December 2021
Abstract: According to the Togolese Policy and Regulatory Overviews on Clean Energy, the residential sector in Lomé accounts for nearly 60 percent of the total electricity consumption. This fact is especially due to the current nature of the economy. A system dynamics model was built using Stella software to estimate both the current and long-term household electricity consumptions. These near (2030) and far future (2050) energy forecasts were carried out for Lomé, the capital city of Togo. Two different models were not only built, but also calibrated utilizing data from the past sixteen years as a benchmark. The first model was built based on the: 1) population, 2) Gross Domestic Product (GDP) growth, and 3) per capita electricity consumption. The second model was solely based on the: 1) number of households with electricity and 2) households accessing electricity. Results revealed that the population of Lomé under the current birth rate will be close to 3 million in 2030 and 5 million in 2050, with corresponding electricity consumption close to 860 GWh and 3 TWh, respectively. Therefore, growth in population, economy, and number of households with electricity will continue to drive the future electricity consumption in Lomé. This study could help investors and policy-makers to set the necessary investments by ensuring a timely, reliable, and resilient electricity supply at the turning of 2050 in the city of Lomé and the country at large.
Abstract: According to the Togolese Policy and Regulatory Overviews on Clean Energy, the residential sector in Lomé accounts for nearly 60 percent of the total electricity consumption. This fact is especially due to the current nature of the economy. A system dynamics model was built using Stella software to estimate both the current and long-term household ...
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