Aboveground Storage Tanks Research Articles

Key Issues of Salt Cavern Flow Battery

Salt cavern flow batteries (SCFBs) are an energy storage technology that utilize salt caverns to store electrolytes of flow batteries with a saturated NaCl solution as the supporting electrolyte. However, the geological characteristics of salt caverns differ significantly from above-ground storage tanks, leading to complex issues in storing electrolytes within salt caverns. Therefore, investigating and summarizing these issues is crucial for the advancement of SCFB technology. This paper’s innovation lies in its comprehensive review of the current state and development trends in SCFBs both domestically and internationally. First, the current development status of SCFB energy storage technology both domestically and internationally is summarized. Then, eight main issues are proposed from the perspectives of salt cavern geological characteristics (tightness, conductivity, ions, and temperature) and electrolyte properties (selection, permeability, corrosion, and concentration). Finally, a novel SCFB system is proposed to address the most critical issue, which is the low concentration and uneven distribution of active materials in the current SCFB system. The review in this paper not only comprehensively summarizes the development status of SCFBs both domestically and internationally, but also points out the direction for the future research focussing on SCFBs.

Deep neural networks for external corrosion classification in industrial above-ground storage tanks

This paper uses transfer learning and fine-tuning approaches to explore EfficientNet smaller models for a multiclassification task of corrosion types in above-ground storage tanks. Data augmentation was used to increment the data an oil and gas company provided, reaching a dataset of around 5000 images. The images were stored in Google Drive and imported into Colab to train the models using TensorFlow and Keras. After the hyperparameters’ tuning a transfer learning model was selected and explored with fine-tuning. The EfficientNetB0 model delivered from fine-tuning accomplished 94 % performance. This work is the first attempt to deploy an artificial vision automatic tool for being implemented during tank inspection in the industrial sector. In further development, this model can be coupled with one based on object detection to remotely identify failures due to external corrosion issues, improving safety and reliability in oil and gas operations.

Analysis of the electromagnetic effects on the large floating roof oil tanks by nearby lightning strike based on TLM

Lightning fire is one of the biggest dangers for chemical and petrochemical storage tank farms, particularly in floating roof oil tanks (FROTs). To improve the lightning protection of FROTs, the process of floating roof tanks affected by lightning is analyzed. Lightning inductive effects can result in the undesired operation of the above-ground storage tank equipment and endanger exploitation safety. The time domain finite element analysis based on the transmission line model (TLM) method is regarded as a numerical technique to solve field problems by implementing circuit equivalents. This study aims to analyze lightning strike characteristics using the Heidler current function and simulate electromagnetic field strength (EMFS) distribution and surface current density (SCD). Calculation of minimum possible effective strike distance and shielding effectiveness (SE) is performed. Parametric modeling ensures accurate modeling of the roof's bypass conductor to the shell. By utilizing the Parameter Sweep technique, multiple simulations can be carried out with varying structure parameter values. This approach ensures optimal efficiency and accuracy in the results obtained.

Assessing the Effectiveness of Regional Storm Surge Reduction Strategies and Tank Level Structural Mitigation Measures for Aboveground Storage Tanks

The effectiveness of regional storm surge reduction strategies and tank-level structural mitigation measures in reducing the failure probability of aboveground storage tanks (ASTs) were studied. Given past failures during flood and hurricane events, several studies have developed fragility models for ASTs. However, the suitability of these fragility models for different hurricane hazard scenarios is unknown. Furthermore, to combat climate change and sea level rise, several regional storm surge reduction strategies are being proposed. However, the effectiveness of these strategies in improving the safety of ASTs is also unknown. So, herein, a framework was proposed that facilitates assessing the suitability of fragility models and the quantification of AST failures and their consequences while propagating uncertainties using Monte Carlo simulations. The application of the proposed framework to Cameron, Louisiana, provided several key insights: (1) fragility models that do not model wave loads and dislocation failure are not suitable for the region; (2) a regional risk mitigation strategy was insufficient for lowering future spill volume, repair, and cleanup costs; and (3) considering bottom-plate failure of anchored tanks—a structural risk mitigation measure—would lead to a 47–72% reduction in the consequences of tank failure.

Remotely sensed above-ground storage tank dataset for object detection and infrastructure assessment

Remotely sensed imagery has increased dramatically in quantity and public availability. However, automated, large-scale analysis of such imagery is hindered by a lack of the annotations necessary to train and test machine learning algorithms. In this study, we address this shortcoming with respect to above-ground storage tanks (ASTs) that are used in a wide variety of industries. We annotated available high-resolution, remotely sensed imagery to develop an original, publicly available multi-class dataset of ASTs. This dataset includes geospatial coordinates, border vertices, diameters, and orthorectified imagery for over 130,000 ASTs from five labeled classes (external floating roof tanks, closed roof tanks, spherical pressure tanks, sedimentation tanks, and water towers) across the contiguous United States. This dataset can be used directly or to train machine learning algorithms for large-scale risk and hazard assessment, production and capacity estimation, and infrastructure evaluation.

The Static and Dynamic Behavior of Steel Storage Tanks over Different Types of Clay Soil

Steel storage tanks are widely used in different fields. Most of these tanks contain hazardous materials, which may lead to disasters and environmental damage for any design errors. There are many reasons which cause the failure of these tanks such as excessive base plate settlement, shear failure of soil, liquid sloshing, and buckling of the tank shell. In this study, five models of above-ground steel storage tanks resting over different types of clay soils (medium-stiff clay, stiff clay, and very stiff clay soils) are analyzed using the finite element program ADINA under the effect of static and dynamic loading. The soil underneath the tank is truly simulated using a 3D solid (porous media) element and the used material model is the Cam-clay soil model. The fluid in the tank is modeled depending on the Navier–Stokes fluid equation. Moreover, the earthquake record used in this analysis is the horizontal component of the Loma Prieta Earthquake. The analyzed tanks are circular steel tanks with the same height (10 m) and different diameters (ranging from 15 m to 40 m). The soil under the tanks has a noticeable effect on the dynamic behavior of the studied tanks. The tanks resting over the medium-stiff clay (the weakest soil) give a lower permanent settlement after the earthquake because of its low elastic modulus which leads to the absorption of the earthquake waves in comparison to the other types of soil. There are 29.6% and 35.6% increases in the peak dynamic stresses under the tanks in the cases of stiff clay and very stiff clay soils, respectively. The maximum values of the dynamic vertical stresses occur at a time around 13.02 s, which is close to the peak ground acceleration of the earthquake.

A comparative numerical evaluation of linear anode arrangements for enhancing above ground storage tank cathodic protection via mesh grid and concentric ring designs

Cathodic protection as a complementary method is one of the most effective ways to prevent corrosion, along with coating and choosing the suitable material. There are different ways to protect the storage tank bottom. Due to the presence of the geo membrane layer and its effective and pivotal role, the use of mixed metal oxide (MMO) anodes is highly recommended. In the current study, the protection process of the above-ground storage tank bottom is simulated using MMO backfilled wire (concentric rings) and ribbon anodes (mesh grid system). In this regard, several parameters must be considered in reaching the protection criteria. The simulation results show that the effect of the limiting oxygen current density, soil resistivity and the anodic current have the greatest role. Anode depth and the spacing between the anodes are also critical factors if they have large values. Due to the importance of the number of conductor bars and feeding cables, two configurations have been presented for ribbon anodes. These configurations have a direct impact on grid resistance, rectifier size, and related costs. Finally, an economic comparison has been made regarding the use of sacrificial and MMO anodes in the form of ribbon next to wire anodes. The results show that, in the use of ribbon anodes, MMO anodes have better performance than magnesium and zinc sacrificial anodes, and the cost required for MMO linear anodes is far lower than the method of sacrificial ribbon anodes. In the present study, the cost of the MMO linear anode system is approximately 20% of zinc and magnesium sacrificial ribbon anode system cost.

Evaluating the Integrity of High-Density Polyethylene Storage Tanks

Failure of high-density polyethylene (HDPE) aboveground storage tanks (ASTs) causes numerous environmental, ecological, and economic problems. Therefore, it is necessary to routinely inspect the integrity of ASTs to identify the potential defects and act before a catastrophic failure happens. This study investigated the feasibility of using infrared thermography (IRT) for routine HDPE AST inspections and how weathering impacts the properties of HDPE. Moreover, the factors affecting the IRT’s accuracy for defect detection were researched, and it was attempted to determine the minimum levels of defect detection for each weather circumstance. This study investigated the potential areas for tank failure for close inspection. Results showed that IRT is efficient in detecting shallow defects within the outer half of the wall. The smallest detectable defect size was 2.8 mm, which varied in different measurements depending on the interaction of sample geometry, initial thermal gradient, and defect location.

Analyzing and design of mesh ribbon cathodic protection for aboveground storage tanks

Aboveground storage tanks are widely used for storage of liquids. The bottom of these tanks rest on the soil and is prone to the corrosion. Due to the use of geo-membrane liner in some cases, the bottoms of these tanks can only be protected from corrosion by using distributed mesh ribbon anodes. Up to now, there is no an accurate and comprehensive calculation for current distribution in such configurations. For this reason, the spans of the ribbon anodes and conductor bars are mostly chose based on simple and handy formulas, which may not be correct and optimum enough. Therefore, in this paper, the current distribution is calculated based on a 2D model and considering coating and polarization effect and then applied for determining the anodes span. Furthermore, the current attenuation in the ribbons and conductor bars are calculated for determining the spans between the conductor bars. Finally, based on the achieved formulas, two designs are presented and compared and the results of them are validated by Finite element method simulations. The results of this paper could be used for optimum design of cathodic protection systems for bottom of the above ground storage tanks.

Nitrogen transformation processes catalyzed by manure microbiomes in earthen pit and concrete storages on commercial dairy farms

Storing manure is an essential aspect of nutrient management on dairy farms. It presents the opportunity to use manure efficiently as a fertilizer in crop and pasture production. Typically, the manure storages are constructed as earthen, concrete, or steel-based structures. However, storing manure can potentially emit aerial pollutants to the atmosphere, including nitrogen and greenhouse gases, through microbial and physicochemical processes. We have characterized the composition of the microbiome in two manure storage structures, a clay-lined earthen pit and an aboveground concrete storage tank, on commercial dairy farms, to discern the nitrogen transformation processes, and thereby, inform the development of mitigation practices to preserve the value of manure. First, we analyzed the 16S rRNA-V4 amplicons generated from manure samples collected from several locations and depths (0.3, 1.2, and 2.1–2.75 m below the surface) of the storages, identifying a set of Amplicon Sequence Variant (ASVs) and quantifying their abundances. Then, we inferred the respective metabolic capabilities. These results showed that the manure microbiome composition was more complex and exhibited more location-to-location variation in the earthen pit than in the concrete tank. Further, the inlet and a location with hard surface crust in the earthen pit had unique consortia. The microbiomes in both storages had the potential to generate ammonia but lacked the organisms for oxidizing it to gaseous compounds. However, the microbial conversion of nitrate to gaseous N2, NO, and N2O via denitrification and to stable ammonia via dissimilatory nitrite reduction seemed possible; minor quantities of nitrate was present in manure, potentially originating from oxidative processes occurring on the barn floor. The nitrate-transformation linked ASVs were more prevalent at the near-surface locations and all depths of the inlet. Anammox bacteria and archaeal or bacterial autotrophic nitrifiers were not detected in either storage. Hydrogenotrophic Methanocorpusculum species were the primary methanogens or methane producers, exhibiting higher abundance in the earthen pit. These findings suggested that microbial activities were not the main drivers for nitrogen loss from manure storage, and commonly reported losses are associated with the physicochemical processes. Finally, the microbiomes of stored manure had the potential to emit greenhouse gases such as NO, N2O, and methane.

Field Inspection of High-Density Polyethylene (HDPE) Storage Tanks Using Infrared Thermography and Ultrasonic Methods

High-density polyethylene (HDPE) is widely used for above-ground storage tanks (ASTs). However, there are currently no guidelines for the non-destructive testing (NDT) and evaluation (NDE) of HDPE ASTs. Moreover, the feasibility, limitations, and challenges of using NDT techniques for the field inspection of HDPE ASTs have not been well established. This study used both infrared thermography (IRT) and ultrasonic testing (UT) for the field inspection of HDPE ASTs. Highlighting the implementation challenges in the field, this study determined that: (1) ambient environmental parameters can affect IRT accuracy; (2) there is an ideal time during the day to perform IRT; (3) the heating source and infrared camera orientation can affect IRT accuracy; and (4) with proper measures taken, IRT is a promising method for flaw detection in HDPE ASTs. Additionally, UT can be used following IRT for detailed investigation to quantify the size and depth of defects. The manuscript concludes with a discussion of the limitations and best practices for the implementing of IRT and UT for HDPE AST inspections in the field.

Fragility assessment of bottom plates in above ground storage tanks during flood events

This study aims to improve the fundamental understanding on the performance of bottom plates in above ground storage tanks (ASTs) during flood events. To this end, fragility models that estimate the probability of material yielding and rupture in the bottom plates were derived. A significant number of ASTs are located in coastal areas and are susceptible to hurricane hazards. Consequently, ASTs have suffered severe damage during past hurricanes resulting in spills with catastrophic environmental and social impacts. Therefore, several failure modes such as flotation, buckling, and sliding have been studied in past research. However, the literature lacks studies that consider the failure of bottom plate due to uplift pressure generated during floods and there are no design guidelines to address this issue. To address this gap, fragility functions that provide the probability of failure as a function of tank geometry, material properties, design parameters, and hazard conditions were developed herein. For this purpose, Latin Hypercube Sampling was performed to span the space of these parameters uniformly. For each parameter combination, maximum stresses in bottom plates were determined using analytical formulations for simply supported and clamped boundary conditions and were compared against two different failure thresholds. The results were used to develop a closed form fragility model using step wise logistic regression. Fragility functions were applied to four case study tanks. Sensitivity analysis were performed to understand the impacts of different probability density functions for various variables on the bottom plates’ fragility. The results provided several insights such as ASTs with larger diameter were vulnerable to bottom plate failure. Comparison with other failure modes revealed that the probability of bottom plate failure was higher than flotation failure for anchored ASTs with clamped boundary condition.

Drone Based Inspection of Above Ground Storage Tanks. A Multi Criteria Evaluation Approach

Unmanned Aerial Vehicles (UAVs) is an emergent technology with the potential to drastically change the landscape of many civil and industrial activities in the near future. A promising field of application is the inspection and monitoring of industrial plants, where UAVs can be a valid alternative to traditional approaches with a better cost-effectiveness and a higher safety level. Although the disruptive innovative potential of this technology is generally recognized, a consistent methodological approach towards the evaluation of the drawbacks and benefits of employing UAVs in critical industrial operations can hardly be found in the current scientific literature. In such context, this paper proposes a framework for assessing the effectiveness of UAV technology in industrial monitoring applications within a structured multi-objective framework. In particular, the paper compares the traditional ground-based inspection services of Above Ground Storage Tank (AST) with UAV based inspection, by means of the well-known Analytic Hierarchy Process (AHP) method considering time, cost and safety criteria. A case study is also proposed to demonstrate the effectiveness of the approach proposed.

A hybrid algorithm for studying the effects of various uncertainties on the nonlinear dynamic responses of steel storage tanks subjected to seismic base excitation

Uncertainty in the basic load and strength variables of a steel storage tank can significantly affect its structural performance and safety. Additionally, due to the inherent uncertainties affecting the various sources in practical situations, their handling in the nonlinear modeling methodology has nowadays become essential. However, it is still an issue to be investigated. Thus, this paper presents a numerical modeling methodology intended to determine the effects of various uncertainties on the dynamic responses of the liquid-shell systems of aboveground steel storage tanks under seismic base excitations. The uncertainties include mechanical properties of materials, geometry properties, liquid properties, and excitation parameters. The uncertain dynamic response of large steel aboveground storage tanks is investigated by using a hybrid algorithm. Eight tall liquid storage tanks with aspect ratios greater than unity are considered. The considered tanks have a similar radius but different heights. The effects of aspect ratio and liquid level on nonlinear dynamic responses are discussed. The point estimation method and the artificial neural network-based algorithm were used to simulate the sources of uncertainty and extract the statistical properties, including the probability density functions (PDF), and the cumulative distribution functions (CDF). An efficient approach with low computational cost compared to the conventional finite element method is proposed based on a combination of the boundary element method and the semi-analytical finite strip to analyze the flexible steel storage tanks subjected to seismic base excitation. Concentric annular rings are used to model the free surface of the liquid. The nonlinearities corresponding to both material properties and geometry deformations are included. According to uncertainty sources, a sensitivity analysis is also carried out. The results show that lognormal probability distribution is more suitable for predicting nonlinear dynamic responses of steel storage tanks under seismic base excitations.

Effect of mitigation on the catastrophic failure of storage tanks

This work investigates the effect of incorporating mitigation techniques on the catastrophic collapse of above-ground storage tanks in terms of dynamic pressures and overtopping fractions using Computational Fluid Dynamics (CFD). Catastrophic Overtopping Alleviation of Storage Tanks (COAST) and Mitigation of Tank Instantaneous Failure (MOTIF) protection measures are implemented. COAST is a deflector fitted to the top of the bund wall that is a structure surrounding a storage tank and MOTIF is a baffle fitted inside the storage tank. An optimisation study has been conducted to select the optimum mitigation technique and the optimum inclination angle of COAST. Subsequently, the effect of incorporating mitigation techniques using different capacities and shapes of bund wall is investigated along with the effect of using various heights of the fluid within the tank. Results show that COAST alone is more effective than combining the two mitigation techniques and the optimum inclination angle giving the lowest dynamic pressures and overtopping fractions is 80°. COAST significantly reduces the overtopping fractions ranging between 93% and 98% for the various capacities investigated. The highest reduction corresponds to a bund wall capacity of 200% of the capacity of the tank. The effect of COAST in reducing the overtopping fractions is more significant for circular shapes than square, rectangular, and triangular walls. Regarding the height of the fluid, COAST is more effective for tall tanks compared to middle and squat tanks.

Stiffness requirements for wind girders in open-top cylindrical steel tanks

Aboveground cylindrical storage tanks are very thin shell structures which are prone to buckling when subjected to wind pressure. Both external and internal pressures are developed due to wind action, and the magnitudes of the pressures generally vary around the circumference. A wind girder is generally used in open-top cylindrical tanks to increase their resistance against buckling. The wind girder must have adequate strength and stiffness in order to fulfill its function properly. Widely used design specifications provide recommendations for the design of the wind girder. Strength requirements are given in terms of stress resultants, while a minimum second moment of area is provided as a stiffness requirement. The recommendations for the stiffness requirement were developed by conducting Linear Elastic Bifurcation Analysis (LBA) of cylindrical shells subjected to uniform external pressure. This paper explores stiffness requirements for the wind girder in open-top cylindrical steel tanks. The relationship between the buckling strength and the second moment of area of the wind girder was explored through a finite element parametric study. Tank shells with different radius-to-thickness and height-to-diameter ratios and having different wind girder sizes were investigated by means of LBA. A buckling strength curve was developed based on the LBA results where the strengths can be predicted with 90% accuracy. In addition, a new second moment of area requirement was proposed. The parametric study was extended to investigate the behavior using Geometrically Nonlinear Analysis including Imperfections (GNIA). The same tank geometries were studied using GNIA and considering different imperfection amplitudes. A buckling strength curve, which takes into account imperfection amplitudes, was developed to be used in design.

Research on the Safety and Security Distance of Above-Ground Liquefied Gas Storage Tanks and Dispensers.

Many countries lack clear legal requirements on the distance between buildings and petrol station facilities. The regulations in force directly determine the petrol station facilities’ required distance to buildings, and such distances are considered relevant for newly designed and reconstructed buildings. Public buildings must be located no closer than 60 m to the above-ground liquefied gas tanks and liquid gas dispensers. Still, based on engineering calculations and the applied technical measures, it is possible to determine a safe distance for buildings that are constructed, extended and reconstructed, to which superstructures are added or whose utilisation method changes. The paper presents the results of calculations devoted to determining a safe distance between public buildings and LPG filling station facilities, using selected analytical models. The analyses were carried out for the LPG gas system commonly used in petrol stations, consisting of two gas storage tanks of 4.85 m3 capacity each, and a dispenser. It is legitimate to eliminate the obligation to observe the 60 m distance between LPG filling stations and public buildings and the mandatory distance of 60 m between liquefied gas dispensers and public buildings is not justified in light of the implemented requirements to use various protections at self-service liquefied gas filling stands.

Using the acoustic emission method for testing aboveground vertical storage tank bottoms

This paper presents use of the acoustic emission (AE) method for diagnostic testing of aboveground vertical storage tank bottoms. This method allows evaluation and location of active corrosion damage of bottom material and micro-leaks in the tested object. To prepare a tank for AE testing, it is not necessary to drain the storage medium, which provides a high state of security with significant diagnosis and operational cost savings. The methodology and AE test results carried out on three storage tanks of crude oil are presented. Data recorded during the measurements have been analyzed. The conclusions drawn from this analysis give the location of detected AE sources and an evaluation of the integrity of the tank bottoms. Assessment of detected acoustic sources allowed for classification of tank bottom surface conditions and estimation of the recommended operational time until the next required test.

Failure Mode Determination of American Petroleum Institute 12F Shop-Welded Tanks With a New Roof-to-Shell Junction Detail

Abstract The American Petroleum Institute (API) 12F is the specification for vertical, aboveground shop-welded storage tanks published by the API. The nominal capacity for the twelve tank designs given in the current 13th edition of API 12F ranges from 90 bbl. (14.3 m3) to 1000 bbl. (159 m3). The minimum required component thickness and design pressure levels are also provided in the latest edition. This study is a part of a series research project sponsored by API that dedicates to ensure the safe operation of API 12 series storage tanks. In this study, the twelve API 12F tank designs presented in the latest edition are studied. The elastic stress analysis was conducted following the procedures presented in the ASME Boiler and Pressure Vessel Code 2019, Section VIII, Division 2 (ASME VIII-2). The stress levels at the top, bottom, and cleanout junctions subject to the design pressures are determined through finite element analysis (FEA). The bottom uplift subjected to design pressures are obtained, and the yielding pressure at the roof-shell and shell-bottom junctions are also determined. The specific gravity of the stored liquid is raised from 1.0 to 1.2 in this study. A new roof-shell attachment detail is proposed, and a 0.01 in. (0.254 mm) gap between the bottom shell course and the bottom plate is modeled to simulate the actual construction details. In addition, the flat-top rectangular cleanout presented in the current edition of API 12F is modeled. Moreover, various thickness combinations are considered to further investigate the effect due to different component thicknesses.

Delaware Basin Case History Details Economic Benefit of Water-Recycling Program

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 204166, “Turning Produced Water Into an Asset: A Delaware Basin Case History,” by Dustin Aro, SPE, and Steven Fowler, SPE, Precision Petroleum Solutions, prepared for the 2021 SPE Hydraulic Fracturing Technology Conference and Exhibition, held virtually 4–6 May. The paper has not been peer reviewed. Well completion operations are affected by freshwater procurement costs starting at approximately $0.75/bbl. Regardless of final fracturing design, water consumption during fracturing operations typically exceeds 500,000 bbl, or $375,000 per well at the time of writing. Significant value exists for recycling produced water by an on-lease pit that can be used for future fracturing operations. The case history outlined in the complete paper explores a multiwell sectional development in the Delaware Basin by a small operator that reduced drilling and completion costs, along with lease operating expenses, by turning undesirable produced water into an asset. Regulatory Considerations Because the Delaware Basin straddles two states, it is important to understand the guidelines and processes of pursuing produced-water recycling operations in Texas as opposed to New Mexico. The operations discussed were executed and managed on the Texas side. While contractor familiarity can be beneficial during the planning stages, the operator also must be well-versed in applicable regulations. It is advisable to consult with legal counsel regarding liability should an unplanned discharge event occur. Lease Development History Before the beginning of initial completions operations, three freshwater wells were drilled on-lease with the intention of use for fracturing operations. The flow rate from the three wells was insufficient to keep up with fracturing operations by an aboveground storage tank (AST). A large-volume fracturing pit was not constructed. The initial completion on Well 1, targeting the Wolfcamp C bench, was executed primarily with fresh water sourced from a third-party pit that was transferred to a nearby AST. During production, Well 1 maintained a high water cut (greater than 90%) and produced a significant amount of water over time. Additional infrastructure would be required to fully exploit the existing freshwater wells as a source for future completions activity. Operator break-even treatment costs have been determined to be the most favorable when using a centralized pipeline water-management program. A pit would act as a centralized gathering point with temporary pipeline infrastructure for water-transfer purposes. An internal economic analysis was undertaken to determine construction costs for a pit that could accommodate 500,000 bbl or 1,000,000 bbl of fresh water. The option of constructing a pit that could handle produced water also was included for comparison.