Crude Oil Storage Tanks Research Articles

Deformation and Stress Prediction of Tank under Uneven Settlement

Abstract The differential settlement of crude oil tank foundations can lead to deformation and stress concentration, posing significant risks to the safe operation of storage tanks. This study developed a finite element model for a large crude oil storage tank subjected to harmonic settlement to address the issue of non-uniform settlement around the tank. The model systematically varied the tank’s diameter-to-thickness ratio, height-to-diameter ratio, and the wind beam’s relative bending stiffness. The research examined the impact of these three factors on the maximum dimensionless radial displacement at the tank top and the maximum equivalent stress at the tank bottom. A predictive method was proposed for estimating the radial displacement at the tank top and the equivalent stress at the tank bottom under uneven settlement, offering valuable insights for assessing the integrity of large tanks in such conditions.

Heat transfer characteristics of oil receiving and delivering process in crude oil storage tanks

The study used numerical simulation methods to investigate the influence of different oil receiving and delivering cases on the non-uniform physical field within the storage tank. The results showed that the evolution of the physical field can be divided into three stages: diffusion, suppression, and equilibrium. The computational domain was divided into three zones based on the crude oil heating rate: significant influence zone, indirect influence zone, and minimal influence zone, and the indirect influence zone exhibits the most pronounced variations in velocity and temperature. The process of receiving oil with high-flow rate and low-temperature was found to be more conducive to the full use of heat in the tank when the heat exchanging quantity per unit time was the same. The synergistic effect of tubular heating and oil receiving and delivering resulted in a 21 % higher average temperature increase rate than the sum of the two processes. Finally, the study quantitatively described the linear relationship between the average temperature in each region and factors such as oil inlet velocity, oil receiving temperature, oil receiving and delivering time, and heating tube temperature, providing theoretical guidance for process planning in actual oil storage tank receiving and delivering.

Aspects Regarding of Oil Sludge Cleaning from Crude Storage Tanks Using Robots

One of the problems of the oil industry is the accumulation of sludge at the bottom of crude oil storage tanks. Oil sludge obtained from crude oil storage tanks is a semi-solid waste. It is actually a complex emulsion made up of numerous petroleum hydrocarbons, water and solid particles or mineral impurities from the rock. Oil sludge is generated during the storage of crude oil production, but also during the transportation, storage, and refining of crude oil. Through its nature - organic and inorganic, dark brown / black in color and semi-fluid physical state - it is a very dangerous waste, as it includes many poisonous substances, such as: polycyclic aromatic hydrocarbons, xylene, benzene, ethyl benzene, toluene, but also metals heavy. Therefore, oil sludge deposition is a dynamic, long-term, and ever-changing process. The authors, under the auspices of AOȘR and AGIR, present - through this scientific paper - a modern technology used for the successful cleaning of oil sludge from crude oil storage tanks and, obviously, it can be a recommendation for organizations in the oil industry.

Quantitative risk assessment of leakage accident of crude oil storage tank based on fuzzy Bayesian network and improved AHP

Leakage accidents of crude oil storage tanks (LACOST) occasionally occur during the production and storage processes of the petroleum and chemical industry, significantly impacting lives, the environment, and private property. To enhance the risk assessment of LACOST, our study sought to construct a fuzzy Bayesian network (FBN) through expert evaluation based on an improved analytic hierarchy process (AHP). Subsequently, the societal risk of LACOST was analyzed in conjunction with the surrounding population density. Applying the proposed method to a crude oil storage depot in China revealed that incorporating the improved AHP significantly enhances the FBN's risk assessment capability, leading to more accurate predictions of LACOST likelihood. Furthermore, the importance of basic events was assessed, thereby effectively and reliably identifying critical events of LACOST. The rationality of the layout of buildings and population density in the oil depot was assessed through societal risk analysis. Collectively, our findings demonstrated that the proposed method can effectively identify changes in both LACOST probabilities and consequences, enabling decision-makers to optimize risk management strategies and achieve efficient resource allocation.

Effect of mechanical stirring on heat transfer and flow of crude oil in storage tanks under different heating methods

Mechanical stirring can promote uniform distribution of crude oil temperature and increase the heating rate, but the effect is different for different heating methods in crude oil storage tank. In this paper, jet heating and tubular heating are used as the heating methods in the tank, the physical and mathematical models under the synergy of two heating methods and mechanical stirring are established, FVM and SIMPLE algorithm are used to numerical calculate. The results show that mechanical stirring can enhance the flow of crude oil in the tank, affect greatly the temperature and velocity fields of crude oil and improve uniformity of the temperature field. Mechanical stirring has more significant effect on tubular heating for the 1000 m3 actual oil storage tank. For tubular heating, mechanical stirring can increase the crude oil average velocity 13.8 times, heating rate by 0.123 °C/h, heating efficiency by 8.37 % and reduce the temperature variance by 92.03 % during 2h of heating. At the same time, the indicators of economic benefits for different heating methods are put forward, and the order of energy consumption per unit temperature rise is obtained: Tubular heating > Jet heating > Jet heating and stirring > Tubular heating and stirring.

A dynamic risk assessment model based on multidimensional and quantitative inference theory

With the continuous increase in petroleum consumption and the trend towards more refined management, crude oil storage tanks are playing an increasingly crucial role in the petrochemical industry. However, the corrosion issue of crude oil storage tanks has consistently been a major factor limiting their service life, and leaks in crude oil tanks are often attributed to corrosion of the tank bottom. Due to the high cost and complexity associated with tank opening inspections, in this paper, directly observable information and physical quantities are utilized as indirect evidence, combined with Bayesian network, to indirectly determine the probability of tank corrosion. This approach allows for selective internal tank inspections, enabling effective risk assessment while also facilitating cost savings. Some parameters in the Bayesian network model are obtained through a probability estimation model combining expert experience and fuzzy set theory. Finally, the feasibility of the method is demonstrated by citing examples. The current model can offer a relatively reliable reference for evaluating the risks associated with tanks and their ancillary facilities, while also reducing the costs of tank inspections to some extent.

Flow coupling analysis and evaluation of different working conditions for crude oil storage tanks under dynamic heating

AbstractDuring periods of sharp demand increase, there is a need for significant expansion in the fundamental requirements for crude oil storage. As demand rapidly escalates, the prerequisites for crude oil storage necessitate substantial expansion. To scientifically and effectively reduce energy waste associated with heating oil, it is essential to study the heating methods and efficiency of crude oil storage tanks. Considering environmental temperature, solar radiation, and the physical properties of the oil, we have proposed a new heating model to elucidate the dynamic heating process of large floating roof storage tanks equipped with coils. Computational fluid dynamics (CFD) software was used to analyze the impact of the dynamic heating model on the temperature and velocity fields within the floating roof tank, taking into account different initial oil temperatures, oil levels, wind speeds, and types of crude oil during the winter heating process. Additionally, the research suggests the optimal maintenance heating temperature and duration for crude oil storage tanks during the winter season, introducing heating efficiency and inhomogeneity of temperature field as two evaluation metrics to compare the advantages of the dynamic heating method over traditional heating methods. This study provides fresh insights into the coil heating domain in crude oil storage tanks.

Converting Iraqi Hazardous Crude Oily Sludge into Value-Added Activated Carbon using KOH Activation Technique

Annually, a high amount of hazardous oily sludge (OS) is produced by North Refineries Company (NRC) Baiji. This work aims to study the specifications of oily sludge in crude oil storage tanks and to convert it into activated carbon (AC) by pyrolysis using KOH activated agent. The physical properties of OS have been measured and analyzed. The AC is produced by carbonizing oily sludge to char under N2 flow using KOH at an impregnation ratio of 2:1 KOH/char. The pore structure, morphology of the surface, and surface chemistry of the AC produced were characterized using Brunauer-Emmet-Teller (BET), Fourier Electron Scanning Electron Microscopy (FESEM), and Fourier-Transform Infrared Spectroscopy (FTIR). The result shows the surface area of the produced AC was 350 m2/g with a mesoporous structure. Based on the findings, the obtained surface area of the AC indicates the oily sludge was a light precursor, which is helpful in producing gas and liquid fuels rather than solid fuel.

Effect of tetrakis(hydroxymethyl)phosphonium sulfate (THPS) on the microbial community and corrosion of carbon steel in a simulated crude-oil storage tank environment

The biocorrosion process has been a problem for the oil and gas industry, involving deterioration of facilities, loss of oil quality, metal loss, and oil leaks. In oil storage tanks, the presence of a metallic surface along with crude oil and water poses a biocorrosion risk. Biocides are used to control the biocorrosion of different metallic infrastructures, tetrakis(hydroxymethyl)phosphonium sulfate (THPS) is commonly used due to its low environmental impact and its effectiveness in preventing sulfate-reducing bacteria (SRB) growth. The treatment effect with one THPS application on microbial community and corrosion rates was evaluated in a batch fractionated assay containing water from a crude oil storage tank, carbon steel coupons and crude oil. The effects of the treatment were monitored for 60 days. The number of planktonic bacteria and archaea estimated by qPCR decreased at the beginning of the treatment with THPS, however, 60 days after the application their number was higher, as were the sulfate-reducing microorganisms (SRM) and methanogens (MA). The diversity analysis of the 16S rRNA gene showed that the relative abundance of the genus Desulfovibrio and Methanocalculus was higher on day 8 in the presence of THPS, but by day 60 there were no differences. The biocide did not inhibit bacterial and archaeal biofilm attached to the SAE 1010 carbon steel coupons and produced a decrease in corrosion rates by blocking the surface. The proximity of the corrosion potential to the pitting potential indicated a high susceptibility to localized corrosion. The results suggested that the changes in the microbial community by THPS treatment were related to the corrosion rates of carbon steel, rather than the number of microorganisms attached to the coupon.

An improved Manson–Coffin model for fatigue life prediction of large crude oil storage tanks via environment temperature and surface roughness

An improved Manson–Coffin model for fatigue life prediction of large crude oil storage tanks via environment temperature and surface roughness

Research on intelligent perception and decision system for special welding mechanical arm of float plate in crude oil storage tank

Abstract In the rapid development of the petrochemical industry in the context of the increasing number of large tanks, large tanks in the production and installation process encountered the first problem the pontoon plate welding deformation and weld seam is too large and other defects, through the construction of the ship plate welding special robotic arm of the intelligent perception and decision-making system to solve such defects. Summarize the Structure of crude oil storage tanks and welding process characteristics based on the ultrasonic distance measurement in the distance sensor to obtain the characteristic data set, combined with the distinct data and computer programming language to build the intelligent perception and decision-making system of the unique robotic arm for ship plate welding. They set the relevant parameter values based on simulation experiments on the welding of a particular robot arm perception and decision-making system for the application of example analysis. Compared to the traditional LSTM algorithm, the YOLO-v5 network-driven weld target detection algorithm has a 5.5% higher accuracy and a 9.1% higher success rate in time robustness evaluation. In addition, the welding decision model based on the DDPG algorithm possesses excellent computational accuracy, and the average error of each parameter in the welding decision of the ship plate is controlled within 5%. This study greatly improves the welding quality of the pontoon plate of crude oil storage tanks and provides solid technical support for the successful completion of the project.

Investigation of residual stress in epoxy-based coatings using X-ray and FEM-ANN techniques

Residual stresses play a significant role in the properties and performance of epoxy-based coatings, with their origins rooted in various factors encountered during production and application. This study focuses on quantifying residual stresses in three distinct epoxy-based coatings, commonly used as linings for crude oil storage tanks, namely, pure epoxy, Novolac epoxy, and glass-flake-reinforced epoxy. We employ X-ray diffraction to measure these residual stresses and compare them against predicted values obtained through finite element and artificial neural network methods. Our findings reveal notable differences in residual stresses among the three types of epoxy coatings. Specifically, pure epoxy coatings exhibit higher residual stresses, Novolac epoxy coatings display the lowest, and those reinforced with glass flakes fall in between. Utilising the FEM-ANN model for simulations yields results that closely align with experimental measurements obtained via the X-ray method. Test results demonstrate that the coatings cured at high temperatures have high residual stresses compared to those cured at lower temperatures. Increasing the curing temperature from 10 to 50oC will increase residual stresses by 40.81, 11.085, and 56.98% for coatings reinforced with glass-flake, Novolac, and pure epoxy-based coating, respectively.

Study on unsteady natural convection heat transfer of crude oil storage tank based on fractional-order Maxwell model

When considering the natural flow processes in crude oil in static storage tanks, researchers usually treat the nonlinear heat and mass transfer and flow using integer-order models. However, this ignores the nonlinear convection and heat-transfer phenomena that occur; these are dependent on time and space due to the viscoelasticity of crude oil, which is a non-Newtonian fluid. In this work, we examined the time and space dependence of the nonlinear natural convective heat-transfer processes in crude-oil storage tanks. Fractional-order Maxwell and Cattaneo–Vernotte models were applied to the traditional momentum and temperature equations considering the Boussinesq approximation. Based on the L1 discrete format, the fractional-order pressure-correction equation was derived, and an associated solver, CaputoTemporalFractionalFoam (CTfracFoam), was developed to simulate the convection processes in static crude-oil storage tanks. The results show that when α equals 0.1, the maximum velocity in monitoring area 2 is 0.1404 m/s, and the velocity gradually increases as α increases with a maximum value of 1.1468 m/s at 0.9. When the β is 0.1 and 0.2, the temperature changes in the transition region are −5.204 and −0.165 °C, respectively, while when β is greater than 0.2, the temperature changes are all positive values with a maximum value of 1.924 °C at 0.9. Compared with integer-order Fourier heat-transfer and Newtonian fluid-flow models, the developed fractional-order model can describe the natural convection phenomena of non-Newtonian fluids such as crude oil more flexible and accurately.

A corrosion assessment methodology based on triangular intuitionistic fuzzy comprehensive evaluation (TIFCE) with analytic network process (TIFANP): An application to external corrosion of the storage tank floor

The increasing demand for oil, natural gas, and green energy has led to massive construction of storage and transportation infrastructure, and the resulting corrosion problems have attracted increasing attention. The complexity of the factors influencing corrosion and the uniqueness of infrastructure pose great challenges to the inspection, assessment, and prediction of corrosion. This challenge is reflected in the large number of influencing factors and the intricate interrelationships between them, which often require the involvement of experts in the assessment. However, due to reasons such as incomplete data and the complexity of corrosion mechanisms, there is uncertainty in the expert's judgment. To address this problem, this work proposes a multilevel, multi-index framework for corrosion evaluation. This framework integrates both analytic network process and comprehensive evaluation method under an intuitionistic fuzzy environment. It uses the triangular intuitionistic fuzzy numbers-based analytic network process (TIFANP) to establish and analyze the weights of the interactive and employed triangular intuitionistic fuzzy comprehensive evaluation (TIFCE) to address the subjective judgment and uncertainty issues in corrosion evaluation. The introduction of the intuitionistic fuzzy concept effectively handles the uncertainty in corrosion assessment. To verify the feasibility and practicability of the framework, it was applied to external corrosion assessment of the floor of a crude oil storage tank. Soil corrosion, cathodic protection, coating protection, and stray current interference were considered the main factors influencing the external corrosion of the storage tank floor. The assessment results were consistent with the open-tank inspection. This work can provide valuable information for storage tank operation, corrosion protection, and maintenance to reduce economic losses and safety accidents caused by the corrosion of crude oil tank floors.

Study on the bacteria consortium for treating tank cleaning oily sludge and its synergistic degradation mechanism

Oily sludge discharged from crude oil storage tanks has received widespread attention. In this work, a consortium with the high-efficient degradation ability of TPH in oily sludge was developed. Screening of the high-efficient single strain and the effective combination by different strains were conducted in a liquid system supplemented with TPH extracted from the tank cleaning oily sludge as the sole carbon source. Among the tested strains, strain NYGH, strain T1, and strain T2 showed relatively higher values of biomass and degradation efficiency of TPH. The consortium contained 50 % of strain NYGH and 50 % of strain T2 led to about 91 % TPH degradation within 5 days. Compared to that of the systems with a single strain, the degradation efficiency of the TPH of the system with the optimized consortium increased by 17.53∼34.38 %. This may benefit from the complementary effect of priority metabolic carbon sources of strain NYGH and strain T2. The slurry phase degradation experiment of tank cleaning oily sludge by the consortium led to a 78 % TPH degradation within 9 days. It suggested that the optimized consortium containing strain NYGH and strain T2 has great potential as the candidate for bioremediation of oily sludge.

An advanced treatment process for 3-high wastewater discharged from crude oil storage tanks.

The wastewater discharged from crude oil storage tanks (WCOST) contains high concentrations of salt and metal iron ions, and high chemical oxygen demand (COD). It belongs to "3-high" wastewater, which is difficult for purification. In this study, WCOST treatments were comparatively investigated via an advanced pretreatment and the traditional coagulation-microfiltration (CMF) processes. After WCOST was purified through the conventional CMF process, fouling occurred in the microfiltration (MF) membrane, which is rather harmful to the following reverse osmosis (RO) membrane unit, and the effluent featured high COD and UV254 values. The analysis confirmed that the MF fouling was due to the oxidation of ferrous ions, and the high COD and UV254 values were mainly attributable to the organic compounds with small molecular sizes, including aromatic-like and fulvic-like compounds. After the pretreatment of the advanced process consisting of aeration, manganese sand filtration, and activated carbon adsorption in combination with CMF process, the removal efficiencies of organic matter and total iron ions reached 97.3% and 99.8%, respectively. All the water indexes of the effluent, after treatment by the advanced multi-unit process, meet well the corresponding standard. The advanced pretreatment process reported herein displayed a great potential for alleviating the MF membrane fouling and enhanced the lifetime of the RO membrane system in the 3-high WCOST treatment.

Study of main factors influencing unsteady-state temperature drop in oil tank storage under dynamic thermal environment coupling

With the increasing oil demand, the construction of oil energy reserves in China needs to be further strengthened. However, given that there has been no research on the main influencing factors of crude oil temperature drop in storage tanks under actual dynamically changing environments, this paper considers the influence of dynamic thermal environment and internal crude oil physical properties on the fluctuating changes in crude oil temperature. A theoretical model of the unsteady-state temperature drop heat transfer process is developed from a three-dimensional perspective. According to the temperature drop variation law of crude oil storage tank under the coupling effect of various heat transfer modes such as external forced convection, thermal radiation, and internal natural convection, the external dynamic thermal environment influence zone, the internal crude oil physical property influence zone, and the intermediate transition zone of the tank are proposed. And the multiple non-linear regression method is used to quantitatively characterize the influence of external ambient temperature, solar radiation, wind speed, internal crude oil density, viscosity, and specific heat capacity on the temperature drop of crude oil in each influencing zone. The results of this paper not only quantitatively explain the main influencing factors of the oil temperature drop in the top, wall, and bottom regions of the tank, but also provide a theoretical reference for oil security reserves under a dynamic thermal environment.

Natech risk assessment for crude oil storage tanks using fish bone diagram

As natural events like storm, earthquake, or flood can have vast areas of impact. Natural disasters have the potential to cause significant impacts on both industrial areas and civil infrastructures like the power plants, communication towers, overhead transmission lines, road transportation, emergency and rescue services etc.). As both Industrial sectors and civil infrastructures are interdependent, such an event can have cascading effects resulting in catastrophes that span regional, national, and international borders. Analysis of past Natech incidents reveals that storage tanks are most susceptible to natural hazards compared to other oil and gas installations. The present paper discusses Natechs that are involved with the storage of hazardous material and also examines the Natech laws and emphasizes the significance of better understanding the interconnectivity of infrastructure failures related to storage tanks and their societal consequences.

Improved solid radiation model for thermal response in large crude oil tanks

In a crude oil tank farm, a fire in a large crude oil storage tank can spread to its neighbouring tanks due to thermal radiation causing wall rupture. To better understand the thermal radiation of tank fires and the thermal response of their neighbouring tanks, a semi-empirical radiation model is proposed in this paper. The model takes into account the smoke generation and its effect in reducing thermal radiation, as well as the variation of flame temperature and emissivity along the flame axis. Compared with existing models, the model is able to predict the radiant heat flux of the flame more accurately, and this advantage becomes more pronounced as the diameter of the pool fire increases.Using the improved model, the effect of different crude oil contents on the thermal response and failure time of the storage tank under the action of thermal radiation was innovatively explored by numerical simulation. An in-depth analysis of the failure time was performed, and an empirical equation was derived to provide a reference for fire emergency management of large storage tanks.

Investigation of microbial diversity in crude oil storage tanks of Isfahan oil refining company, Iran

Investigation of microbial diversity in crude oil storage tanks of Isfahan oil refining company, Iran