Aboveground Storage Tanks Research Articles

Field scale ex-situ bioremediation of petroleum contaminated soil under cold climate conditions

Assessment and development of strategies for ex-situ bioremediation in cold climates, such as in Canada, is of great importance for decontamination of contaminated soils. The purpose of this paper was to evaluate and compare the use of microbial consortia inoculant and mature organic compost as bioaugmentation and biostimulation strategies to enhance ex-situ bioremediation of a soil contaminated with heating oil under cold weather conditions. The soil was impacted as a result of leakage from an above-ground storage tank and had an initial TPH concentration was 940+ 127 μg g−1 (dry weight). Aerobic biopiles of 16 m3 each were constructed and subjected at a field scale to microbial consortia inoculant and 10:1 ratio of mature organic compost. Two biopiles (S) contained only soil as control, two biopiles (S + C) contained soil and compost to assess the individual effect of compost addition, two biopiles (S + M) contained soil and microbial consortium to assess the individual effect of microbial consortium addition, and three biopiles (S + C + M) contained soil plus compost and microbial consortium to assess the combined effect of compost and microbial consortium addition. Over a 94 days period, composite soil samples for each biopile were collected and analysed for total petroleum hydrocarbons (TPHs), volatiles (F1), semi volatiles (F2) and non-volatiles (F3) fractions, microbial counting, and pH. Additionally, field measurements including soil temperature, moisture content, carbon dioxide (CO2) and oxygen (O2) were carried out. Although the ambient temperature varied from −3.5 °C to −24.1 °C, the internal soil temperatures for the different experimental setups maintained above freezing conditions. Results showed that biocell inoculated with microbial consortia and amended with 10:1 soil to compost ratio under aerobic conditions performed the best, degrading 82% of total petroleum hydrocarbons (TPHs) with a first-order kinetic degradation rate of 0.016 d−1, in cold weather conditions. The average removal efficiencies for TPHs after 94 days for S, S + M, S + C treatments were 48%, 55%, and 52%, respectively. Statistical analysis indicated significant difference (p < 0.05) within and between the final measurements for TPHs and significant difference between the treatment with combined effect (S + C + M) and the control (S) as well as individual treatments of S + C and S + M. The study concluded that the combination of microbial consortia inoculation and mature compost as a biostimulant in a 10:1 soil to compost ratio would be an appropriate bioremediation approach for this type of soil matrix, reaching values below provincial standard regulations in just 40 days after construction. This research aimed to provide valuable knowledge to practitioners about cost-effective and existing strategies for ex-situ bioremediation during cold weather conditions.

Seismic response mitigation of chemical plant components by passive control techniques

This paper deals with the applicability of seismic passive control in major-hazard chemical installations. The objective is to show numerically and experimentally the applicability of Passive Control Techniques (PCT) in industrial plants. Consequently, the main components of a process plant are classified and collected into a limited number of classes; for each class, the main damages caused by past earthquakes are described and the most vulnerable components are identified. A synthesis of the effects of earthquakes on the different typologies of process components is also presented and the most suitable innovative seismic protection systems, in particular passive control techniques (PCT), are acknowledged. Finally, the effectiveness of PCT in reducing the seismic response of process plant components is proved by three representative case studies: a base isolated above-ground storage tank, a distillation column connected by elastoplastic dampers to the adjacent service frame and an application of non-conventional Tuned Mass Dampers to a support frame.

고장수목분석법을 이용한 액화천연가스 저장탱크 형식별 위험성 비교 평가

최근 LNG 저장탱크 시장에서는 지상식 멤브레인 LNG 저장탱크의 대용량화 용이성, 친환경성, 내부탱크로부터의 낮은 누출 가능성(완만한 누출속도의 증가) 등의 장점으로 동 탱크의 건설에 대한 적극적인 검토가 이루어지고 있다. 이 논문에서는 고장수목분석법(FTA)을 활용하여 기존의 완전방호식 LNG 저장탱크와의 비교 위험성평가를 통해 멤브레인 LNG 저장탱크의 안전성을 분석하였다. 위험성평가 결과는 추가적인 안전장치를 갖지 않는 초기 멤브레인 LNG 저장탱크를 제외하고 두 형식의 LNG 저장탱크가 매우 유사한 위험수준을 가지는 것으로 나타났다. Building above-ground membrane LNG storage tanks have been recently actively reviewed because they have advantages in ease of large capacity, environmental friendliness, and low possibility of gas leakage of the inner tank (slow increase of leakage speed). In this paper, the safety of membrane LNG storage tanks was ensured through comparative risk assessment of full-containment LNG storage tanks and membrane LNG storage tanks by using Fault Tree Analysis (FTA). Risk assessment results showed that both types of tanks have very similar level of risk except for the membrane storage tanks without additional safety equipments (early model).

The influence of maintenance on the life cycle of above-ground storage tanks

The influence of maintenance on the life cycle of above-ground storage tanks

Risk Based Inspection Methodology and Software Applied to Atmospheric Storage Tanks

A new risk-based inspection (RBI) methodology and software is presented in this paper. The objective of this work is to allow management of the inspections of atmospheric storage tanks in the most efficient way, while, at the same time, accident risks are minimized. The software has been built on the new risk framework architecture, a generic platform facilitating efficient and integrated development of software applications using risk models. The framework includes a library of risk models and the user interface is automatically produced on the basis of editable schemas. This risk-framework-based RBI tool has been applied in the context of RBI for above-ground atmospheric storage tanks (AST) but it has been designed with the objective of being generic enough to allow extension to the process plants in general. This RBI methodology is an evolution of an approach and mathematical models developed for Det Norske Veritas (DNV) and the American Petroleum Institute (API). The methodology assesses damage mechanism potential, degradation rates, probability of failure (PoF), consequence of failure (CoF) in terms of environmental damage and financial loss, risk and inspection intervals and techniques. The scope includes assessment of the tank floor for soil-side external corrosion and product-side internal corrosion and the tank shell courses for atmospheric corrosion and internal thinning. It also includes preliminary assessment for brittle fracture and cracking. The data are structured according to an asset hierarchy including Plant, Production Unit, Process Unit, Tag, Part and Inspection levels and the data are inherited / defaulted seamlessly from a higher hierarchy level to a lower level. The user interface includes synchronized hierarchy tree browsing, dynamic editor and grid-view editing and active reports with drill-in capability.

Buckling of fixed-roof aboveground oil storage tanks under heat induced by an external fire

This paper presents computational modeling and results of steel storage tanks under heat induced by an adjacent fire. In this research, modeling is restricted to the structural behavior of the tank, with emphasis on thermal buckling of the shell. Two tanks that buckled under a huge fire in Bayamón, Puerto Rico in 2009, are investigated in detail: a small tank with a self-supported conical roof, and a large tank in which the conical roof is supported by a set of rafters and columns. For a tank that is empty, the results show that a relatively low temperature is enough to produce static buckling of the shell. In pre-buckling states, the cylindrical shell has thermal expansion; at the critical state the displacements reverse and inwards displacements are observed at advanced post-buckling states. Parametric studies are performed to understand the influence of the shell thickness, the level of fluid stored in the tank, the area affected by fire in the circumferential direction, and the temperature gradient through the thickness. The buckling modes are compared with real deflection of tanks that were affected by fire.

Situation of Aboveground Oil Storage Tanks in China

Situation of Aboveground Oil Storage Tanks in China

Acoustic emission testing of aboveground petroleum storage tanks: Risk assessment and lessons learned

AbstractThis article discusses the in‐service inspection experience of aboveground storage tanks (AST) with the acoustic emission method (AE). The risk assessment is made according to the American Petroleum Institute (API) Publication 353. Weighting factors were developed to modify the risk of each AST after the AE floor inspection and conventional inspection for the shell and roof.Specific procedures are presented through the analysis of elastic waves generated in the tanks by external load. We have considered different noise sources with emphasis in sources caused by leakage of the product to comply with the Argentinian National Regulations in Leak Control. To validate the methodology, we have compared the proposed in‐service inspection and its weighting factors with the traditional inspection (e.g., with magnetic flux leakage).Finally, we have studied the signal interference which is cause from the cathodic protection system. This can lead to an incorrect analysis in the postprocessing. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012

Reduced Stiffness Buckling Analysis of Aboveground Storage Tanks with Thickness Changes

The Reduced Stiffness Analysis (RSA) to compute lower bounds to buckling loads of shells has been employed by a number of researchers as a simple way to evaluate the buckling capacity of shells that display unstable behavior and imperfection-sensitivity. It allows the use of simple eigenvalue analysis, without having to perform incremental nonlinear analysis, and is based on the physical behavior of the shell which recognizes that a significant contribution to the stability of a shell under lateral pressure is provided by its membrane stiffness. Unstable post-critical behavior is associated with the loss of this stabilizing membrane contribution. Past use of the approach has been mainly restricted to cases of uniform shell thickness and uniform pressures in the circumferential direction, in which case analytical solutions are possible. Recent applications by the authors and other researchers have shown ways to compute the lower bounds using finite element analysis, for which a modified eigenvalue analysis is constructed by neglecting the membrane contributions to the matrix containing the initial stresses. This paper illustrates the application of the methodology to cases of pressure loaded shells with thickness changes in the meridional direction. A semi-analytical finite element code has been employed for the buckling analysis when uniform pressures act on aboveground steel tanks. The tanks are representative of those constructed for the oil industry, with diameter to thickness ratios of the order of 3000, and height to diameter ratios lower than one.

Hurricane and Flood Preparedness for Aboveground Storage Tanks

Abstract In 2005 Hurricanes Katrina and Rita cased over ten major (> 100,000 gallons) oil spills and medium (> 10,000 gallons) oil spills in coastal areas of Texas and Louisiana. The volume for these spills was approximately eight (8) million gallons, which is just over half the volume of the Exxon Valdez event (1989). After these natural disasters caused such an environmental impact, the Federal Region 6- Regional Response Team (RRT) Executive Committee charged the Science and Technology Chair to form a committee to investigate these situations and make recommendations. The committee included representatives from several federal and state agencies, including: US Environmental Protection Agency (USEPA), US Coast Guard (USCG), US Department of Energy (USDOE), National Oceanic and Atmospheric Administration (NOAA) and Texas General Land Office (GLO). It also included several representatives from the involved industry. The committee then decided to take a head-on approach by tasking each member to focus on h...

지상식 LNG 저장탱크용 고강도 자기충전 콘크리트의 최적배합에 관한 연구

This study is to performed to find the optimum mix proportion of the high strength and self compacting concrete for the above-ground LNG storage tank construction and field application. If LNG storage tank wall thicknesscan be reduced, the construction cost and quality can be improved by using self-compacting high strength concrete with compressive strength 60~80 MPa. For this purpose, low heat cement (Type IV) and class F fly ash are used in concrete mix to control hydration heat, flowability, and viscosity. Mix design variables of unit water, fly ash replacement ratio, water-binder ratio, and fine aggregate ratio are selected and tested for material properties and manufacturing cost of the concrete. Also, fly ash replacement ratio is considered using confined water ratio test. The test results showed that the optimum mix proportion of the self-compacting high strength concrete characteristics are as follows. 1) In case of the concrete with specified compressive strength of 60 MPa, the optimum mix proportion is fly ash replacement ratio of 20% and water- binder ratio of 27~30%. 2) In case of the concrete with the strength of 80 MPa, the optimum mix proportion is fly ash replacement ratio of 10% and water-binder ratio 25%. But unit water and fine aggregate ratio are 165 and , respectively, regardless of the traget concrete compressive strength range. Also, test results showed that concrete manufacturing cost of 60 MPa and 80 MPa concrete require additional costs of 14~22% and 33%, respectively, compared to the manufacturing cost of 40 MPa concrete. Therefore, application of the self-compacting high strength concrete has proven to be economical in the perspective of the material cost, quality control, and site management.

Henry’s Equilibrium Partitioning between Ground Water and Soil Air: Predictions versus Observations

Humans spend 64% - 94% of their time indoors; therefore, indoor air quality is very important for potential exposure to volatile organic compounds (VOC). The source of VOC in the subsurface may come from accidental or intentional releases, leaking landfills or leaking underground and above-ground storage tanks. Once these contaminants are present near or beneath buildings, they may move as a vapour through soil gas and enter the building. A large number of vapour intrusion (VI) algorithms have been published in peer-reviewed publications that link indoor VOC concentrations to the contamination of soils. These models typically include phase partitioning calculations of VOC based on Henry’s law to estimate the concentration of a particular contaminant in soil gas. This paper presents the results from a series of laboratory experiments concerning the use of the Henry’s Law constant for the calculation of toluene concentrations in equilibrium between ground water and soil air. A series of column experiments were conducted with various toluene concentrations in artificial (ground) water to contrast the predicted and observed (soil) air concentrations. The experiments which exclude soil material show a toluene fugacity behaviour roughly in line with Henry’s law whereas the experiments which include soil material result in equilibrium soil concentrations which were around one order-of-magnitude lower than was expected from a Henry Law-based estimation. It is concluded that for toluene inclusion of Henry’s Law in VI algorithms does not provide an adequate description of volatilisation in soils and may lead to an overestimation of health risk. Instead, a model based on a simple description of the relevant intermolecular interactions could be explored.

Optimal Structural Design of Circular, Rotationally Molded, Above-Ground Polyethylene Water Storage Tanks

Rotationally molded polyethylene water storage tanks have been produced since the 1950s when the technology became available for this manufacturing process. For circular tanks manufactured in this way, the traditional method of design has been based on hand calculations considering internal hydrostatic pressure from the stored liquid as the primary applied load. This study presents the results of the optimal structural design of 16 circular polyethylene water tanks of various sizes. Based on the results derived, optimal design recommendations for these tank structures are provided when both hydrostatic pressure and wind loads are applied.

Synthesis of Unloading Operation Procedure for a Mixed Operation of Above-Ground and In-Ground Liquefied Natural Gas Storage Tanks Using Dynamic Simulation

Because of increased liquefied natural gas (LNG) demand, operation of LNG receiving terminals having both above-ground and in-ground LNG storage tanks will soon be required. In such cases, there exists a pressure head difference between the two types of tanks. As such, during the depressurization step of LNG unloading, vapor can be generated at the top of the unloading pipeline of the above-ground tank due to pressure head. Vapor produced in a branch pipeline of the above-ground tank can thereby cause congestion during depressurization, resulting in a pressure difference across the unloading valve. This can, in turn, cause excessive boil off gas inflow into the storage tank. In this paper, we suggest a reliable unloading operation procedure for a mixed operation of above-ground and in-ground storage tanks using dynamic simulation.

New Technologies and Robotic In-Service Inspections for Aboveground Storage Tanks

New Technologies and Robotic In-Service Inspections for Aboveground Storage Tanks

Removal of Methyl Tert-Butyl Ether from Air-Groundwater in Environment by Carbon Nanotube: Ab Initio Studies

ABSTRACT Gasoline and heating oil travel through pipelines and are also distributed by truck to above-ground and underground storage tanks. Through its extensive use as a fuel oxygenate, methyl tert-butyl ether (MTBE) is found nearly ubiquitously throughout the environment. MTBE, a widely used gasoline additive, is recently being scrutinized for potential environmental damage in groundwater and in the atmosphere. We study the structural, total energy, thermodynamic, and conductive properties of absorption of MTBE on carbon nanotube (CNT), which converts to CO and H2O. There are four situations for MTBE to be near by single-walled nanotube (SWNT) that we have investigated its adsorption on CNT and convertion to other products. The thermodynamic properties are calculated for them. The calculations have quantum mechanical detail and are based on a semiempirical (MNDO method), which is applied to the evaluation of both the electronic structure and of the conductance.

Higher order modes cluster (HOMC) guided waves for online defect detection in annular plate region of above-ground storage tanks

Corrosion detection in the annular plate region of above-ground storage tanks is a critical needfor tankfarm operators in the oil and gas industry. The critical zone between the tank shell wall and the first few inches of the annular plate is difficult to inspect with conventional floor scanning methods due to the presence of coatings, uneven surfaces and a lack of access due to the presence of the weld toe. This region, however, is prone to accelerated corrosion due to the additional stresses caused by the weight of the tank wall and the increased possibility of water entrapment under the annular plate. Repairs in this region demand replacement of the entire annular plate and this leads to long shutdown of the tank, and often failures occur without any warning. A new method using the Higher Order Modes Cluster Guided Waves (HOMC * ) to detect and screen defects in the critical inaccessible zones in the annular plate is discussed. This testing can be carried out online while the tank is in operation using HOMC guided waves generated on the outer exposed region of the annular plate. Robotic scanners allow for the inspection to be carried out in relatively short periods of time. Data collected in the laboratory as well as from the field trials are presented. The HOMC technique has potential for non-destructive inspection of inaccessible regions in structures for medium-range applications (2 to 3 m).

Research Trends on Structural Design of Floating Roofs in Aboveground Storage Tanks

Research Trends on Structural Design of Floating Roofs in Aboveground Storage Tanks

Differentiation of leakage and corrosion signals in acoustic emission testing of aboveground storage tank floors with artificial neural networks

The acoustic emission method is a well-recognized procedure of floor inspection for aboveground storage tanks as well as a preventive tool for the improvement of maintenance service time. The high importance of this method is better realized when it is used in sensitive structures while they are in operation. A laboratory-based smaller-scale tank was made and all operating conditions were simulated. This provided a databank for recognition of acoustic waves. More experiments were conducted to simulate corrosion in a tank. Data were then collected from acoustic emission measurements for several aboveground storage tanks in a refinery. The data gathered from laboratory tests and the real data were combined in order to differentiate between leakage and corrosion signals. An artificial neural network (ANN) system was used to categorize the tested aboveground storage tanks.

Simplified Calculations of Impressed Current Anode Bed Resistance Underneath Tank Bottoms

Abstract Impressed current cathodic protection using uniformly distributed ribbon anodes has proven to be effective in controlling the corrosion of soil-side aboveground storage tank bottoms. Parallel and concentric ribbon anodes are two of the most common patterns of laying anode beds some distance underneath tank bottoms. At the design stage, the rule-of-thumb approach and historical data are used to determine the spacing between ribbon nodes. Computer-aided finite element analysis is potentially also available to assist in determining anode distributions. However, because of its complexity, this approach is not used frequently in practice. In this work, we address the design issue by taking a simplified approach based only on the geometries and the cathodic protection current requirement. The equations derived enable the determination (using a pocket calculator) of the number of concentric or parallel anodes, the spacing between them, and the anode bed resistances. Support of the derived resistance equ...