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The temperature drop process of waxy crude-oil in an oil tank is an unsteady natural-convection process involving multi-substance coupling, multi-heat transfer coupling, phase transformation, solid-liquid interaction, rheological change, fluid-solid coupling and turbulence, and the heat transfer process is highly complicated. According to the influence of the phase change process of waxy crude-oil on the heat transfer process, based on the new three-phase partition method, the phase change heat transfer model of waxy crude-oil in an oil tank was established, and the finite volume method was used to carry out the equation discretization and solution. Through numerical simulation, the evolution laws of the temperature field, flow field, and growth of the condensate layer during the cooling process of oil in the tank were analyzed. The results had theoretical guidance and significance for the scientific design of the oil tank's thermal insulation structure. [ABSTRACT FROM AUTHOR]

Arc discharge caused by short-circuit faults is one of the most serious faults in UHV transformers， with the potential for inducing deformation， rupture， burning， or even explosion of the oil tank. In order to analyze the stress-strain levels induced by arc discharge in transformers， a finite element model for a 1，000 kV single-phase UHV transformer was established. The simulation and analysis focused on the pressure distribution within the oil tank caused by arc discharge at different locations and energy levels. Stress-strain levels in both the oil tank and bolts were calculated， with a comprehensive safety check on their mechanical properties based on material parameters. Additionally， the discharge energy thresholds leading to tank wall rupture or bolt damage were determined. The findings reveal that the maximum stress during arc discharge near the high-voltage winding in the oil tank is located at the corner of the tank wall， and the maximum deformation is observed in the middle of the tank wall along the long axis. Furthermore， the maximum stress during arc discharge inside the lifting seat is concentrated at the support of the elevated seat， with the maximum deformation observed at the turning point of the elevated seat.

Copyright of Zhejiang Electric Power is the property of Zhejiang Electric Power Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, a unique method for using thermoelectric generators (TEGs) to generate electricity is introduced, a technique that makes use of a cold oil tank and hot exhaust gases from generators. A set of TEGs and an integrated cold oil tank are connected to the diesel generator as part of the suggested design. A pertinent thermal modeling was designed and a thorough parametric study was carried out to show the validity of this innovative concept. The parametric study has demonstrated that when the generator power and the thickness to thermal conductivity ratio of each TEG in the system are increased, the temperature differential in each TEG module and the power produced by the assembly of TEGs both exhibit linear increases. The length of the TEG plate and the height of the exhaust gas duct cause an exponential increase in the temperature differential across each TEG module. The TEG assembly's power output increases linearly with TEG surface length and decreases exponentially with exhaust gas duct height. Using an exhaust gas duct height of 0.05 m, and a TEGs plate length of 1 m, the parametric study showed that power generation of up to 2778 W is feasible under the predetermined circumstances of a diesel generator with an output of 125 kW. When compared to a conventional setup, the new hybrid generator in this scenario may be able to increase power generation by up to 2.22 %.

A new concept of power generation from thermoelectric generators TEGs using the hot exhaust gas of boilers and a cold oil tank is proposed. The suggested concept consists of a flow of exhaust gas of boilers and cold oil in a tank separated by a plate comprising several TEGs in series. The oil tank at the bottom of the system constitutes the cold convection condition for the TEG plate and the upper hot exhaust gas flow constitutes the hot convection condition. Accordingly, a temperature gradient is created across the thickness of the TEGs, which play the role of a separation plate, and converted to an electrical power. To justify the feasibility of this new concept, a suitable thermal modeling is developed and the associated parametric analysis is carried out. The parametric analysis reveals that powers up to 622 W can be generated with a system having a space heating load of 200 kW, an exhaust gas duct height of 0.05 m, and a TEG plate length of 1 m. The temperature difference across each TEG module decreases exponentially when the TEGs plate length increases and decreases exponentially when the exhaust gas duct height increases.

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article discusses a modular robotic self-propelled installation on a caterpillar track (hereinafter referred to as a self-propelled installation). It is delivered on a special fire truck for fire extinguishing. With different equipment it is capable to cut out windows in the wall of a burning tank with oil products and to feed foam inside. There is presented the composition of modules as well as a detailed description and technical capabilities of a self-propelled installation for extinguishing a tank with oil products.

The leakage of tank oils, once occurred, will bring about adverse effect to ambient environment, social economy and safety of tank farm, and even cause safety accident. Herein, the leakage diffusion process of oil and gas was simulated with the improved Gaussian puff model to find out the concentration distribution law of oil and gas in tank farm under different environmental wind speeds and atmospheric stability. Meanwhile, the tank farm was divided into the explosive hazardous area, flash fire hazardous area and suffocation hazardous area according to the risk level of oil and gas concentration. By analyzing the influence of environmental wind speed and atmospheric stability on migration and diffusion of oil and gas puff, the influence law of environmental conditions of tank farm on concentration distribution of oil and gas, as well as the scope of hazardous area, was obtained. Specifically, the migration and diffusion of oil and gas puff is intensified with the increasing of environmental wind speed, but the concentration of oil and gas in the tank farm is reduced, and the hazardous areas of different grades are reduced accordingly. With the increase of atmospheric stability, the diffusion of oil and gas puff becomes weaker, the influence range of concentration along the downwind direction increases, but the influence range along the crosswind direction decreases. Because of the fluctuation of wind speed, the oil and gas puff may gather and form an oil and gas accumulation area at high concentration. Generally, the lower the environmental wind speed and the more stable the atmosphere, the easier the oil and gas puff to gather. The improved Gaussian puff model may more accurately reflect the leakage diffusion law of oil and gas, and predict the concentration distribution of oil and gas, which could provide guidance to the safe operation and management of tanks.

As the most vulnerable part of the aircraft,the fuel tank is damaged by hydrodynamics ram effect when attacked by high-speed projectiles,which will directly threaten the safety of the aircraft.The numerical research on the hydrodynamics ram effect is of great significance.In this paper,CEL(coupled Eulerian Lagrangian)method is used to simulate the hydrodynamics ram effect.Firstly,the accuracy of the numerical model is verified by comparing with the existing experimental results;Then,the effects of impact velocity and liquid filling rate on the hydrodynamics ram effect are analyzed.Finally,in order to reduce the damage power of hydrodynamics ram effect,the design of protective structure is numerically analyzed.The results show that the damage power of hydrodynamics ram effect comes from shock wave.The greater the kinetic energy of projectile and the higher the liquid filling rate,the greater the damage of oil tank.The protective baffle can reduce the damage caused by shock wave to the oil tank structure to a certain extent,and the air-interlayer protective structure is the best for the protective effect.

[Display omitted] • The tank sludge measurement experiment system is designed and built. • Measurement of sludge deposits in storage tanks. • Prediction method of sludge based on Three-Dimensional Residue Recovery Algorithm. • Identification of sludge boundary in threshold segmentation method. • The error of the proposed method is within 5% in the experiments. Non-contact sludge measurement methods for storage tanks can address the challenge of measuring the volume of sedimented sludge during long-term storage. While infrared thermography technology can address the issue of liquid level detection, its measurement accuracy for the undulating interface of sludge is insufficient. This study designed and constructed experimental setups for measuring sludge in storage tanks. In this study, infrared images taken by an infrared camera were used to record the temperature distribution of the outer wall of the storage tank. The threshold segmentation method is used to determine the accurate sludge boundary line in image processing. Finally, the Three-Dimensional Tank Residue Recovery Algorithm (3D-TRRA) was applied to fit the 3D distribution of the sludge and calculate accurate sludge volumes. The results indicate that the best segmentation is achieved with a threshold of 170. The measurement error for sludge volume is less than 5%. Accurate visual positioning and recognition of sludge are achieved. [ABSTRACT FROM AUTHOR]

With the enlargement and intensification of oil storages, the technologies and equipment used in the tank farm are quite complicated. Hence, once any fire accident occurs, the domino effect may be triggered with catastrophic consequences. In order to reduce the impact of oil storage accidents on the surrounding personnel and environment, the model of safety barrier was established with the event tree and Bayesian network method by considering the performance of three types of safety barrier, including the active, passive, emergency and response measures, and the probability of the domino effect was evaluated quantitatively. The results show that: the multi-layer safety barriers can reduce the probability of domino effect by 3 to 7 orders of magnitude and the probability of the multi-level domino effect to a greater extent. Besides, the passive protection barrier is the most effective, followed by the emergency and response measures, and the active barrier is the least effective. Generally, the research results can provide some guidance for reducing the damage and impact of regional accidents in the areas where multiple devices are concentrated.

This paper reports an analysis of the frequencies and shapes of oscillations of the tank with a volume of 3000 m³ with a winding of highstrength steel wire with a diameter of 3 mm, 4 mm, and 5 mm, applied in increments of 1:3. In addition, for the tension force of the turn in the range from 0.2 to 0.8 of the yield strength of the wire material. The study was carried out on the basis of a finite-element method in the ANSYS software package for a three-dimensional geometric model of the structure. At the same time, the software took into consideration the height-uneven width of the cylindrical wall taking into account the height of the filling to the maximum height and the tension forces of the winding. It has been established that a change in the diameter of the winding wire does not lead to a significant change in the spectrum for the first ten significant frequencies. And an increase in the tension force of the wire in the winding leads to a decrease in the magnitude of oscillation frequencies. The exception is the sixth frequency. Its values are equal to one-tenth of a Hz for all estimated cases of the force of tension of the turn in the range from 0.2 to 0.8 of the yield strength of the wire material. The oscillation shapes of the tank reinforced by the winding have been determined. The change in the tension force of the wire in the winding does not change the number of waves at the circumferential coordinate at the free edge of the structure. We studied the loss of stability of the tank wall under distributed internal pressure. A comparative analysis of the sixth oscillation shape and the shape of stability loss reveals that they have the same number of waves at the circumferential coordinate. The results reported here could make it possible to effectively use the pre-stress in order to detune the tank from the resonant frequency when operating in seismically hazardous areas [ABSTRACT FROM AUTHOR]

This paper is treated with the lightning overvoltages (LOVs) applied to the roof oil tanks in low voltage distribution systems. Since the oil tanks and electric distribution towers are not usually protected by guard wires, they may be more exposed to lightning strikes. In this way, the grounding system configurations, soil resistivity, the oil tank diameter and even the inherent characteristics of lightning strikes play an important role in the possibility of malfunctioning caused by overvoltages. The simulation results represent that the distance between indirect lightning stroke points discharging to the ground and the oil tank locations can also create destructive LOVs on them, if the grounding system is not well selected and implemented. Power system protection equipment such as surge arresters can greatly reduce these effects, but due to economic limitations, it is not possible to use them extensively and, therefore, it is necessary to limit LOVs using the minimum available facilities like grounding system variation. This paper represents that using meshed grounding systems can better mitigate the corrosion and the hazards of lightning surges than conventional vertical rods with effective length. All mathematical equations and formulations are solved using numerical methods implemented in Fortran. [ABSTRACT FROM AUTHOR]

Copyright of Large Electric Machine & Hydraulic Turbine is the property of Large Electric Machine & Hydraulic Turbine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Detection of moisture content in oil products is an important link to guarantee the safety of aviation fuel. Thus, the oil-water interface measurement of aviation fuel and accurate drainage of water in an automatic way is the inevitable trend for development of aviation fuel storage and management. By comprehensively researching the existing oil-water analysis technology, an oil-water interface measuring method based on the capacitance detection technology was put forward with consideration given to the storage characteristics of aviation kerosene, so as to accurately measure the oil-water interface at the bottom of the aviation fuel tank, and in combination with the process flow and the site control technologies, to realize the automatic drainage of water at the bottom of the tank. The results show that, the measuring method can greatly improve the accuracy of oil-water interface measurement and the automation of water drainage, further to reduce the operation cost resulted from the labors and excessive discharge of kerosene and to improve the information management of oil depot.

Leaking-burning coupling fires caused by oil leakage from tanks cause significant damage to occupants and the equipment. A series of experiments was conducted to investigate the fire behavior of a tank with oil leaking and burning. The tank released n-heptane into the tray below, forming a fire that heated the tank. The tray size and leak diameter varied. Spill fires, steady pool fires, boiling pool fires, and jet fires were observed. The results show that within a specific leak diameter range (2.5-3.5 mm), the maximum pressure increased with decreasing leak diameter. The fuel vapor spread along the bottom of the tank, causing the expansion of the flame. Consequently, the pool fire size was larger than the actual tray size, thereby making the maximum pressure and thermal radiation almost independent of tray size. When the leaking oil began to boil and burn, the pressure increased rapidly and the emitted radiative heat flux was the largest; therefore, fire posed the most serious threat. A computational fluid dynamics (CFD) modeling approach was employed to predict the time when the temperature of the leaking oil reached its boiling point. The predicted results were validated against the experimental ones, which provided useful support for emergency response plans. [ABSTRACT FROM AUTHOR]

Leaking-burning coupling fires caused by oil leakage from tanks cause significant damage to occupants and the equipment. A series of experiments was conducted to investigate the fire behavior of a tank with oil leaking and burning. The tank released n-heptane into the tray below, forming a fire that heated the tank. The tray size and leak diameter varied. Spill fires, steady pool fires, boiling pool fires, and jet fires were observed. The results show that within a specific leak diameter range (2.5–3.5 mm), the maximum pressure increased with decreasing leak diameter. The fuel vapor spread along the bottom of the tank, causing the expansion of the flame. Consequently, the pool fire size was larger than the actual tray size, thereby making the maximum pressure and thermal radiation almost independent of tray size. When the leaking oil began to boil and burn, the pressure increased rapidly and the emitted radiative heat flux was the largest; therefore, fire posed the most serious threat. A computational fluid dynamics (CFD) modeling approach was employed to predict the time when the temperature of the leaking oil reached its boiling point. The predicted results were validated against the experimental ones, which provided useful support for emergency response plans. [ABSTRACT FROM AUTHOR]

If the oil vapor from the tanks is discharged into the atmosphere, the environment pollution will be caused and the human health will be threated. Definitely, pressure and temperature changes are the main factors causing evaporation of oil products in the tank. As for the breathing loss of oil tanks, the formula concerning the minimal reduction rate of the breathing loss of pressure tanks was derived based on the API theoretical formula, so as to reduce the breathing loss, even to completely eliminate the small breathing loss, by controlling the pressure with a breather valve of oil tank. According to the analysis on influence of temperature change on expansion factor of monomer hydrocarbon (propane, n-butane, isobutene, n-pentane and n-hexane) and various oil products (93# gasoline, 97# gasoline, naphtha, kerosene, diesel oil and Panyu crude oil), the results show that when the storage pressure of the tanks is designed for oil products of different types and compositions, tank with different design pressure shall be adopted. In addition, appropriate type of breather valve can be used, or the tank wall can be thickened to increase the control factor, further to reduce the breathing loss of tank. The research results could be used as theoretical reference for oil tank design and oil depot management.

The main factor of oil tank fire spread should be attributed to the fire's heat radiation. Affected by the heat radiation transferred from the flame of the firing tank, adjacent tanks are easily ignited and may cause a widespread fire in the entire tank farm. In order to study the distribution rule of heat radiation on tank wall when adjacent tanks are exposed to heat radiation, the small-sized experimental device of the heat radiation influence of burning tank on adjacent tank a smallscale experimental device for the influence of tank combustion on the heat radiation of adjacent tanks was established to conduct the experimental study on heat radiation distribution of adjacent tank wall under fire conditions. The experimental results show that under fire conditions, the adjacent tank wall in front of the firing tank is most exposed to radiation. The heat radiation drops gradually from the tank roof to the tank bottom and symmetrically from the center line to both sides. As the L/D(L is the distance between two adjacent oil tanks, and D is the diameter of the oil tank) ratio increases, the heat radiation on the adjacent tank decreases. The experimental data can provide a reference for the heat radiation research of adjacent tanks under fire conditions, and is of great significance for preventing adjacent tanks from being ignited and preventing fire and explosion accidents in tank farm.

This paper presents an automatic visual inspection of exterior surface defects of oil tanks using unmanned aerial vehicles (UAVs) and image processing with two cascading fuzzy logic algorithms. Corrosion is one of the defects that has a serious effect on the safety of the surface of oil and gas tanks. At present, human inspection, and climbing robots inspection are the dominant approach for rust detection in oil and gas tanks. However, there are many shortcomings to this approach, such as taking longer, high cost, and covering less surface area inspection of the tank. The purpose of this research is to detect the rust in oil tanks by localizing visual inspection technology using UAVs, as well as to develop algorithms to distinguish between defects and noise. The study focuses on two basic aspects of oil tank inspection through the images captured by the UAV, namely, the detection of defects and the distinction between defects and noise. For the former, an image processing algorithm was developed to improve or remove noise, adjust the brightness of the captured image, and extract features to identify defects in oil tanks. Meanwhile, for the latter aspect, a cascading fuzzy logic algorithm and threshold algorithm were developed to distinguish between defects and noise levels and reduce their impact through three stages of processing: The first stage of fuzzy logic aims to distinguish between defects and low noise generated by the appearance of objects on the surface of the tank, such as trees or stairs, and reduce their impact. The second stage aims to distinguish between defects and medium noise generated by shadows or the presence of small objects on the surface of the tank and reduce their impact. The third stage of the thresholding algorithm aims to distinguish between defects and high noise generated by sedimentation on the surface of the tank and reduce its impact. The samples were classified based on the output of the third stage of the threshold process into defective or non-defective samples. The proposed algorithms were tested on 180 samples and the results show its superiority in the inspection and detection of defects with an accuracy of 83%.

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ordnance Industry Automation is the property of Editorial Board for Ordnance Industry Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The necessity for safety in oil-gas storage and transportation has led to increasing technical requirements for on-line monitoring of damaged pores and oil leakage from tanks. In this study, the severity of damage of the oil tank at the micron level was detected by terahertz time-domain spectroscopy (THz-TDS), which is of great significance for the early detection and prevention of oil leakage. The THz amplitude (EP) was related to the severity of damaged according to the THz-TDS measurement of oil tanks with various degrees of damage, including intact, partially damaged, completely damaged, and seriously damaged points. Absorption and scattering effects co-occurred when the THz wave penetrated the tanks, with the collective tendencies being used to expressly monitor oil leakage from tanks. When the oil tank was damaged to form micron-level pores and the crude oil had not overflowed, the pore size was close to THz wavelength and the Mie scattering effect was obvious. After further destruction of the pores, the crude oil gradually spilled over and the scattering effect was gradually transformed from Mie scattering to Rayleigh scattering. In addition, the polar molecules in crude oil have strong resonance under the irradiation of THz wave, and the THz wave has strong attenuation. Eventually, surface tension of the oil flattens the surface of the tank, the scattering effect is gradually suppressed and replaced by the absorption effect. Absorption and scattering caused by THz waves passing through tanks coexist and have competing relationships. The change rule of EP can successfully prove the phenomenon and can be considered as an important alternative for application to predict the degree of tank damage. Therefore, in this study, the detection of pores as small as micrometers on the oil tank was expected to greatly prevent oil leakage accidents and improve the safety of oil and gas storage and transportation. [ABSTRACT FROM AUTHOR]

Copyright of Energy Chemical Industry is the property of Energy Chemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Display omitted] • A storage tank bottom is protected by impressed current cathodic protection. • Potential and current distribution of the tank bottom is simulated using FEM. • The protection is validated using three criteria of protection using FEM. • Effect of current, anode distance and coating on potential distribution is examined. • It is a guide for evaluating cathodic protection system prior to implementation. Underside failure of storage tank bottoms is a serious industrial problem which is induced by various corrosion phenomena such as under deposit, microbial and stray current corrosion and can lead to leakage of hazardous materials and explosion. Impressed current cathodic protection (ICCP) is a widely used technique to hinder these types of corrosion. However, undue design of the ICCP system can accelerate the corrosion. Therefore, it is necessary to make sure that the tank bottom is totally and properly under protection before implementation. For this aim, a FEM model is designed in this study for validating this presumption. The model is based on the potential and current density distribution of the tank bottom and is designed using the data of a real storage tank being protected in practice. Simulation results showed that the tank bottom's potential with the ICCP applied (considering voltage drop) and its polarized potential at the very first instant of current interruption both are at least −0.850 V vs Cu/CuSO 4. Furthermore, based on the calculations, 0.260 to 0.280 V polarization is experienced by the tank bottom. These results confirm full protection of the tank bottom. Effects of anode arrangement, coating application and soil resistance on the system performance are also investigated and the most optimal design is proposed based on the potential distribution. Conducting such a simulation in advance can significantly increase the life time of the structure. [ABSTRACT FROM AUTHOR]

[Objectives] For the optimization of an oil tank steam heating system,[Methods] the author used the Flowmaster simulation calculation method and tradition calculation method and made comparative analysis on the calculation results to verify the dependability of the calculation results. Two methods were used to examine how ambient temperature,heating coil pipe length,steam flow rate,steam temperature and heating coil pipe HTC(heat transfer coefficient) could affect the heating process.[Results] the calculation results indicate that calculation error margin of the two methods is about 3%~7% and there are design parameters such as a heating coil pipe length and a steam flow rate in the design of the oil tank steam heating system. Both methods have advantages and disadvantages,where simulation calculation is suitable for optimization design while traditional calculation is favorable for preliminary estimation. Combination of the two methods can offset their disadvantages.[Conclusions] The study result can be used as reference for design of oil tank steam heating system.

The establishment of the virtual environment model of the oil tank is helpful to solve the problem that the motion state of the real cleaning robot is unknown when the camera in the oil tank fails, and is the key to the remote operation of oil tank cleaning. Based on this, the modeling research of virtual environment based on OpenGL, VRP, VRML and WTK and the modeling technology of 3D laser scanning environment are introduced in detail from the direction of structured environment. The modeling method and application of 3D scene based on point cloud information and SFM are described from unstructured environment. In addition, the research status, basic steps and problems to be solved in the process of modeling the virtual environment of oil storage tanks are analyzed. Finally, the development trend of modeling the virtual environment of oil storage tanks based on three dimensional scene modeling method based on point cloud information, which can realize real-time interaction, is proposed. [ABSTRACT FROM AUTHOR]

The oil tank can form a considerable amount of sludge deposition after continuous accumulation, which cause a seriously negative impact on both the storage capacity and the safe operation of the oil tank. Therefore, it is important to anticipate the rate of sludge deposition in advance so that proper measures can be planned to remove this heavy layer on the bottom. This paper proposes a method using a relatively simple formula for predicting the sludge deposits. The sedimentation mechanism of wax and asphaltene is introduced and summarized from both the micro and macro aspects, the factors causing the interaction between particles and the influence on coalescence were analyzed. We applied our prediction methods to calculate the sludge deposition of four oil tanks in Mo-he Station and compared our results with the data measured by experiments. The results show that our method had a good general accuracy to experimental data and can be used directly for on-site engineers to anticipate real sludge height before measuring the oil level inside the tank. [ABSTRACT FROM AUTHOR]

Fuel storage tanks are one of the main sources of water pollution as well as loss of crude oil and oil products in refineries. In the process of utilization of these tanks, considerable amounts of hydrocarbons may find their way into the coastal water, which eventually lead to loss of valuable hydrocarbons. Oil type, climatic condition and characteristics of oil tanks are among the main variables in computing evaporative losses. The present study brings out the results of a project that was carried out to investigate the adverse effects of oil terminal on coastal waters of Qeshm Island and aims to elaborate on speciation of metals in coastal waters. For this purpose, 12 stations were sampled. Water chemistry software was used to draw Eh-pH diagrams. Along with the speciation of heavy metals, cluster analysis was carried out by MVSP software. According to the results, HSC diagrams showed that Cu and Cd were present as free ions. Lead, manganese, cobalt, zinc and nickel were respectively present as PbOH, MnOH, ZnOH, CoOH and NiOH in the Persian Gulf. Speciation of Cu and Ni was in the form of Cu2O and NiO. Vanadium was also present in combination with hydroxide. Since all the studied elements were within the water stability range, they were stable, and there were no environmental risks of contamination and toxicity. The results of cluster analysis did not show any relation between Eh and pH. This clearly showed that Eh-pH was governed by different mechanisms in coastal waters of Qeshm Island. Vanadium and Ni concentration was governed by pH, while Cu and Cd concentration was controlled by Eh.

Investigating the effects of single impulse current (SIC) and multiwaveform multipulse currents (MWMPCs) on metal contributes to the body of knowledge on lightning damage characteristics and mechanisms. This information is the basis for lightning protection of metal-made structures such as oil tanks, wires, and aircraft. In this article, three typical impulse currents, the 30-/80- $\mu \text{s}$ waveform current with amplitude of 150 kA, the 2-ms square-waveform current with amplitude of 2 kA, and the 520-ms rectangular-waveform current with amplitude of 404 A, are individually generated to inflict damage to aluminum alloy (Al 3003) for studying the effects of different lightning currents. Results are further compared to the continuously combined application with MWMPC, which is more close to real lightning. The damaged area of alloy suffered from the combined application experiment is 3156.0 mm2 and damaged depth is 4.7 mm, increased by 15% and 42% compared with the extreme results of individual application. In the MWMPC experiment, oxygen content increases to 35.6% and microhardness grows to 78.5, 21% and 2% higher than the extreme in SIC experiments. Damage deepening effect and crack intensifying effect are discovered in the combined MWMPC experiment. This article provides data for lightning protection and damage modeling. [ABSTRACT FROM AUTHOR]

Experimental study of explosion prevention has been performed in the oil tank filled with suppression material. The kerosene in the pool is used as the fuel to ignite the gasoline and diesel oil tank to investigate the impact of suppression material on the degree of the deflagration. The pictorial information and temperature data are recorded by the high-speed camera and infrared imaging device, respectively. The maximum temperature of the fire in the tank within the filling material has apparently declined. The temperature of diesel oil liquid is greater than the diesel oil vapor. On the contrary, the temperature of gasoline vapor will keep arising and surpass the gasoline liquid. In the presence of suppression material, the average rate of temperature rise of the gasoline and diesel oil liquid is about 0.12 and 0.15 K/s, respectively. Damage of heat radiation effects to the human body from different combustion models has been compared with the effect of suppression material. [ABSTRACT FROM AUTHOR]

The thermal radiation intensities at different positions around the full surface fire of oil tank with different types of oil and different sizes of oil tanks were calculated and analyzed based on point source model. The theoretical calculation results were verified by a series ol 20 m2 Full surfaec fire experiments of diesel oil tank. The results indicate that the theoretical calculation results based on point source model are basically consistent with the experimental results. The thermal radiation intensities received by the targets at different positions around the oil tank decreases exponentially with the increase of the distances from the targets to the tank wall. It is found that the thermal radiation intensities are closely related to tank areas and fuel types. The larger the tank area is, the greater the thermal radiation intensity around the tank. For the same area of tank fire, the order from large to small of thermal radiation intensity of different types of fuel is gasoline, diesel, crude oil. It is also found that the ambient wind can cause the center of the flame of tank fire to shift downwind, which can reduce the thermal radiation intensity in the upwind region. This study can provide guidance for scientific rescue of full surface fire of large oil tanks. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of FeS and FeS 2 on the pyrophoricity of ironic sulfide is investigated. • FeS is more prone to spontaneous combustion than FeS 2. • FeS 2 absorbs energy to inhibit the early oxidation reaction of ironic sulfide. • Intermediate product elemental sulfur promotes the later oxidation reaction. • Multi-stage reaction forms a pyrophoric synergistic effect of ironic sulfide. The pyrophoricity of ironic sulfide of sulfur corrosion products in oil tanks is a critical safety and environment concern that may trigger fire and explosion accidents. This paper focused on mixtures of FeS with FeS 2 and aimed to systematically investigate their influence on the pyrophoricity of ironic sulfide. The results showed that the mixtures' oxidation spontaneous combustion processes are generally similar, including low-temperature heating, oxidation decomposition, and burning-out stages. The more unstable molecular configuration and uneven surface morphology of FeS made it more prone to spontaneous combustion than FeS 2. As the proportion of FeS 2 in the sample increased, it absorbed the energy used to activate FeS during the early stages of oxidation and decomposition, causing the sample's activation energy to increase and its pyrophoricity to weaken. When the proportion of FeS 2 reached a certain level, the reaction may produce a large amount of elemental sulfur, which further oxidized and released heat, thus promoting the sample's pyrophoricity. The study results suggest that the oxidation process of ironic sulfide involved a spontaneous, multistage exothermic reaction and produced intermediate products such as elemental sulfur, leading to a synergistic effect that influenced the reaction process. [ABSTRACT FROM AUTHOR]

Object localization is an important application of remote sensing images and the basis of information extraction. The acquired accuracy is the key factor to improve the accuracy of object structure information inversion. The floating roof oil tank is a typical cylindrical artificial object, and its top cover fluctuates up and down with the change in oil storage. Taking the oil tank as an example, this study explores the localization by combining the traditional feature parameter method and convolutional neural networks (CNNs). In this study, an improved fast radial symmetry transform (FRST) algorithm called fast gradient modulus radial symmetry transform (FGMRST) is proposed and an approach based on FGMRST combined with CNN is proposed. It effectively adds the priori of circle features to the calculation process. Compared with only using CNN, it achieves higher precision localization with fewer network layers. The experimental results based on SkySat data show that the method can effectively improve the calculation accuracy and efficiency of the same order of magnitude network, and by increasing the network depth, the accuracy still has a significant improvement.

Since the input power of the real waves varies continuously and periodically, how to stabilise the operation and generation during wave energy utilisation has become an inevitable and significant topic. This study focuses on the wave energy converter of a hydraulic power take‐off (HPTO) connected to a pendulum and studies the influences of the key components, i.e. the high‐pressure accumulator, oil tank and flow control valve, on the operational stability of HPTO by simulations and experiments. Parameters of the high‐pressure accumulator are analysed and optimised. The dynamic performance of the HPTO with or without the oil tank is also investigated. Besides, the functions of the flow control valve in the cases of excessive input power and load shedding are given. Results show that the key components play very important roles in the operational stability of HPTO. Reasonable configurations of the high‐pressure accumulator and oil tank are significant to improve the quality of output power and stability. Appropriate actions of the flow control valve are beneficial to protection and stability. Therefore, these key components should be considered preferentially during the design of HPTO. [ABSTRACT FROM AUTHOR]

The oil tank can form a considerable amount of sludge deposition after continuous accumulation, which cause a seriously negative impact on both the storage capacity and the safe operation of the oil tank. Therefore, it is important to anticipate the rate of sludge deposition in advance so that proper measures can be planned to remove this heavy layer on the bottom. This paper proposes a method using a relatively simple formula for predicting the sludge deposits. The sedimentation mechanism of wax and asphaltene is introduced and summarized from both the micro and macro aspects, the factors causing the interaction between particles and the influence on coalescence were analyzed. We applied our prediction methods to calculate the sludge deposition of four oil tanks in Mo-he Station and compared our results with the data measured by experiments. The results show that our method had a good general accuracy to experimental data and can be used directly for on-site engineers to anticipate real sludge height before measuring the oil level inside the tank.

Abstract The pyrophoric tendency of the powder of corrosion products and deposits in oil tanks was investigated by performing several series of tests in a modified self-heating experimental apparatus based on the crossing point temperature method. Three samples of the powder of corrosion products and deposits in oil tanks as well as a ferrous sulfide were used as test samples. The corresponding apparent activation energies (E a s) were obtained: 26.1 kJ mol−1 for the corrosion products of a crude oil storage tank, 27.2 kJ mol−1 for the middle distillate oil storage tanks, and 43.5 kJ mol−1 for ferrous sulfide; the unexposed cross-point for deposits of a crude oil storage tank was at a temperature below 250 °C. Those values of E a s indicated that the corrosion products of the two oil storage tanks showed a stronger pyrophoric tendency than did the deposits of the crude oil storage tanks and ferrous sulfide. Furthermore, the E a values were similar to those of reactions reported for the incomplete oxidation of hydrogen sulfide (H 2 S), thus supporting the viewpoint that H 2 S may be considered the intermediate product for accelerating the self-heating and self-ignition of sulfide at temperatures below 250 °C and may play a major role in inducing fires and explosions in storage oil tanks. In addition, possible sources of H 2 S in self-heating of the corrosion product were largely caused by thermochemical sulfate reduction or thermal decomposition of the organic matter of oil tanks. Graphical abstract Unlabelled Image Highlights • Corrosion products powder show stronger pyrophoric tendency than ferrous sulfide. • H 2 S may be the major role for accelerating self-heating at temperature below 250 °C. • Possible sources of H 2 S were largely TSR or thermal decomposition of organic matter. • Critical thicknesses of corrosion products were <10 mm at 50 °C. [ABSTRACT FROM AUTHOR]