Steel Storage Research Articles

Multi-objective optimal design and seismic assessment of an inerter-based hybrid control system for storage tanks

In this paper, a hybrid control system (HCS) endowing a base isolation system (BIS) with a Tuned Mass Damper Inerter (TMDI) is proposed for the protection of steel storage tanks from severe structural damages induced by seismic events. Among all the components of industrial plants, cylindrical steel storage tanks are widely spread and play a primary role when subjected to seismic hazard, since they suffer of many critical issues related to their dynamic response such as high convective wave height and base shear force. The adopted base isolation system is realized with spring and damper elements, whereas the TMDI is realized with a tuned mass damper connected to the ground by the inerter. The developed mechanical model consists of a MDOF system, which considers the impulsive and convective modes as well as the TMDI dynamics. An optimal design problem is tackled, making use of a multi-objective approach, with the scope to mitigate simultaneously the convective and impulsive response of the storage tank. A zero mean white noise excitation is assumed as input in the optimal design procedure. Once the HCS is optimally designed, a systematic investigation of its seismic effectiveness is reached through parametric analysis. Modal parameters and frequency response functions are discussed. A literature case study comparing the effectiveness of the proposed optimally designed HCS with traditional base isolation is illustrated and performances are assessed through stochastic excitation and natural earthquakes.

Effect of Bending Process on Microstructure, Mechanical Properties and Crack Formation of 5% Ni Steel

The 5% Ni steel is often used to make steel storage tanks to store liquefied natural gas (LNG). Herein, the microstructure and mechanical properties of 5% Ni steel samples during bending were studied through combining scanning electron microscopy, energy dispersive spectroscopy, optical microscopy, X-ray diffraction, and electron backscattered diffractometer methods with tensile tests. The outer and inner arcs underwent tensile and compressive stress, respectively, resulting in a severely deformed microstructure with a high density of dislocation, improving both the tensile and yield strengths. The ductility of the 5% Ni steel samples decreased significantly after bending due to the work hardening and dislocation accumulation. During bending, the shear bands occurred at the surface or subsurface, which were caused by strain localization. Amounts of “harder” grains with high TF and more orange and red KAM areas with high local strain at the outer and inner arcs produced a greater stress concentration than that of the mid-thickness, which can induce crack initiation and propagation due to the large deformation during bending.

Biaxial bending design of solid steel storage rack uprights in global buckling

This study aims at investigating the biaxial bending capacity of cold-formed steel (CFS) storage rack uprights undergoing global (lateral-torsional) buckling. A previously published and validated biaxial bending numerical model for local and distortional buckling of CFS rack uprights is initially validated in this paper for global buckling and then used to evaluate and analyse the biaxial bending response of nine unperforated upright cross-sections. Nine biaxial bending configurations were considered per cross-section. Results show that a nonlinear interactive relationship typically governs the biaxial bending of the studied uprights. This relationship is discussed and analysed for different cross-sectional slenderness. The numerical capacities are compared with both the classical DSM predictions and the use of inelastic reserve capacity in the DSM. Results show that the classical DSM equations underestimate the biaxial bending capacity by up to 55% but results in better predictions when the inelastic reserve capacity is considered. Finally, an extended range of inelastic reserve strength for global buckling is proposed which results in a 14% improvement of the DSM predictions. The appropriate form of the DSM to estimate the global biaxial bending capacity of unperforated cold-formed steel storage rack uprights is discussed.

Experimental Investigations of the Behavior of Stiffened Perforated Cold-Formed Steel Sections Subjected to Axial Compression

Cold-formed steel sections are becoming popular for different steel structures, because they have a high resistance against different straining actions, with a minimal weight compared with hard steel sections. Recently, perforated cold-formed steel (PCFS) sections have been used in many applications, such as perforated upright storage racks. Experimental research into the behavior of steel storage rack uprights subjected to axial compression is presented in this paper. First, tensile tests determined the material qualities of the cold-formed steel uprights. Then, seventeen perforated specimens were examined under axial compression, with five different cross-sections, three different web heights and thicknesses, and varying lengths. The study’s goals were to find out how perforations affect the performance and failure mode of steel storage rack uprights, to discuss the interaction of distortional and global buckling, and to verify the accuracy of using the direct strength method (DSM) for predicting the ultimate strength before failure in buckling interactions for perforated uprights. It was found that the failure modes of perforated specimens with stiffeners generally cannot be well predicted using the direct strength method. However, when the modifications proposed by Xianzhong Zhao et al. are used, the accuracy is acceptable.

Three-Dimensional Nonlinear Dynamic Analysis of Base Isolated Cylindrical Steel Tank

Failure of a tank during an earthquake can result in significant financial, human, and environmental losses. Thus, their lack of resiliency against strong earthquakes may result in refinery disruption. This has the potential to have a considerable impact on any economic system. As a result, more research into the seismic performance of tank structures is required to attain the highest possible level of resistance against strong earthquakes. In this paper, we aim to look into the installation of seismic isolation systems in cylindrical steel storage tanks. A nonlinear 3D finite element model is developed with ANSYS software. Moreover, tank wall material nonlinearity, fluid-structure-interaction, and sloshing components are considered. The bilinear hysteretic LRB is used for modal and time-history analysis. In this work, three tanks with varying aspect ratios are studied: "Model A", "Model B", and "Model C". Furthermore, the fixed tank's fundamental frequencies were compared to the analytical results of the American API 650 Standard. Subsequently, the dynamic behavior response of the researched tanks to the horizontal component of the El-Centro 1940 earthquake with PGAs of 0.34g and 0.5g is investigated. As a result, the dominating frequency of the seismic isolation system is within the effective frequency range of seismically isolated systems. The results illustrate that the base isolation limits the tank wall movement with a large displacement in the isolators; the mode shape is a cantilever beam in all isolated circumstances. The total seismic response reduction in the slender tanks is greater as compared to the broad case in the base-isolated tanks. The sloshing displacement increases with an increase in the tank aspect ratio. Additionally, the isolation device eliminates tank buckling at the base and top of the tank shell during seismic excitation (elephant foot and diamond buckling). It can be concluded that the seismic isolation technique has a more significant impact on reducing the dynamic response of ground-supported tanks, particularly in taller tanks as compared to broad tanks. Doi: 10.28991/CEJ-2022-08-06-013 Full Text: PDF

Determining the Production and Transport Cost for H2 on a Global Scale

Hydrogen (H2) produced using renewable energy could be used to reduce greenhouse gas (GHG) emissions in industrial sectors such as steel, chemicals, transportation, and energy storage. Knowing the delivered cost of renewable H2 is essential to decision-makers looking to utilize it. The cheapest location to source it from, as well as the transport method and medium, are also crucial information. This study presents a Monte Carlo simulation to determine the delivered cost for renewable H2 for any usage location globally, as well as the most cost-effective production location and transport route from nearly 6,000 global locations. Several industrially dense locations are selected for case studies, the primary two being Cologne, Germany and Houston, United States. The minimum delivered H2 cost to Cologne is 9.4 €/kg for small scale (no pipelines considered), shipped from northern Egypt as a liquid organic hydrogen carrier (LOHC), and 7.6 €/kg piped directly as H2 gas from southern France for large scale (pipelines considered). For small-scale H2 in Houston, the minimum delivered cost is 8.6 €/kg trucked as H2 gas from the western Gulf of Mexico, and 7.6 €/kg for large-scale demand piped as H2 gas from southern California. The south-west United States and Mexico, northern Chile, the Middle East and north Africa, south-west Africa, and north-west Australia are identified as the regions with the lowest renewable H2 cost potential, with production costs ranging from 6.7—7.8 €/kg in these regions. Each is able to supply differing industrially dominant areas. Furthermore, the effect of parameters such as year of construction, electrolyser, and H2 demand is analysed. For the case studies in Houston and Cologne, the delivered H2 cost is expected to reduce to about 7.8 €/kg by 2050 in Cologne (no pipelines considered, PEM electrolyser) and 6.8 €/kg in Houston.

Corrosion Behavior of Carbon Steel in Multiphase Time-Sharing Flow Sewage System

Single well output is poor in several Yanchang oilfield development blocks, water content is high, and hydrogen sulfide is present at the same time. The tank corrosion in the on-site multiphase time-sharing flow sewage system was severe. The coupon method was used to test the corrosion rate and the scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) methods were used to study the corrosion morphology of the coupon and analyze the composition of the corrosion products in order to effectively inhibit corrosion in the storage tank and analyze the physical and chemical properties of the sewage. The corrosion rates of the upper, middle, and lower sections of the incoming water tank increased and subsequently decreased, whereas the corrosion rates of the upper, middle, and lower parts of the filtered water tank decreased. Local corrosion, pitting corrosion, and pit corrosion were observed in the storage tank, with the corrosion products mostly being Fe2O3, FeS, and FeS2. It was determined that the primary corrosion causes in the top section of the carbon steel storage tank were dissolved oxygen and Cl−, sulfur (H2S) and SRB, and SRB in the bottom part. The combination of bacterial, hydrogen sulfide, and oxygen corrosion created the corrosion process.

Stiffness and resistance of brace-to-upright joints with lipped channel braces assembled flange-to-flange

Industrial cold-formed steel pallet racks are constructed of upright frames bolted to braces in the cross-aisle direction. The flexibility and resistance of these brace-to-upright joints play a key role in the structural behavior of pallet racks in the cross-aisle direction. In this paper, the behavior of these joints has been evaluated through monotonic and cyclic experimental tests to determine the dominant failure modes and the stiffness. The resultant cyclic structural response is pinched, which suggests that upright frame connections are non-dissipative. An analytical model based on the Component Method has been developed to evaluate the ultimate resistance and the flexibility of these bolted connections, with braces oriented flange-to-flange. The model is capable of identifying the influence of each component on the connection structural response. A comparison with results obtained by a Finite Element numerical model, typically used in common practice, in which members are modelled by elastic frame elements and connections are assumed rigid is conducted. The numerical model overestimates the effective stiffness by nearly 14 times. The same model, when modified with a linear link with a force-displacement response determined from the analytical model, provides reliable results in agreement with the experiments. The developed modelling approach is recommended for adoption by practitioners for the design of steel storage pallet racks.

Development of friction-damped seismic fuses for steel storage racks

This paper describes a study [1] on the behaviour and design of drive-in racks with fuses installed to reduce seismically imposed internal actions. Two different cross-aisle framing systems were tested using various earthquake signals and magnitudes. The first system featured cross-aisle frames fully braced from top to bottom using diagonal braces. In the second system, the cross-aisle frames were braced from the top down to the level of the first pallet runner. In the former system, the rack structure was found to be very stiff and hence, it attracted high base shear action causing severe damage to the uprights, braces and connections. The latter system was found to be significantly more flexible, attracting much lower base shears. However, due to the inherent flexibility of the latter system, second order effects due to excessive sway could cause instability especially when spatial plastic hinges develop in the uprights. Based on the outcomes of the study, a new bracing mechanism has been developed to improve the seismic behaviour of steel storage racks using friction-damped seismic fuses. This paper presents the new bracing system with integrated seismic fuses including tests of the components of the fuses. Full-scale tests of complete 3-bay drive-in racks are also presented featuring tests in the elastic range to determine the natural frequencies of the two systems and destructive tests of fully loaded racks subject to common earthquake time histories of increasing magnitude. The paper also discusses the opportunity the seismic fuses present to substantially enhance the seismic performance of steel storage racks.

Calibrated Equivalent Viscous Damping for Direct Displacement Based Seismic Design of Pallet-Type Steel Storage Racks

ABSTRACT Direct displacement-based seismic design has been proposed for pallet-type steel storage racks. Damping models are developed in this study for pallet-type steel storage racks in the down-aisle and cross-aisle directions for use in direct displacement-based seismic design. The damping models are developed using results from reversed cyclic tests at a component level or at a system level. Jacobsen’s approach is used to develop a first set of damping models. The damping models are then assessed using results from nonlinear time-history analyses. Finally, the damping models are calibrated using an iterative procedure based on results from nonlinear time-history analyses.

Brittle Fractures of Cylindrical Steel Storage Tanks for Petroleum and Petroleum Products in the North

This article discusses brittle fracture accidents of petroleum and petroleum products storage tanks that occurred in Yakutia. Operational safety of tanks in the cryolithozone is reduced by harsh natural and climatic conditions, the uniform and differential settlements of the shell and bottom, long-term operation associated with the degradation of structures and materials in such climatic conditions. The main factor contributing to brittle fracture is extreme low ambient temperature, which reduces the ductility and resistance to brittle fracture of steel of structures and welds. The uniform and differential settlements of the tank lead to appearance of dangerous stress-strain state of shell and its general and local deformations. A sharp change in the air temperature causes thermal stresses in the statically indeterminate structures of the tank. Analysis of tank accidents in Yakutia shows that places of crack initiation are assembly welds and their heat-affected zones, the metallurgical and corrosion defects of the base metal. Dangerous areas of the tank are shell-to-bottom connections and attachments of piping nozzles to the shell. The main cause of the considered accidents is the use of low-carbon steel that does not recommend to the oil tank operation in the climatic conditions of the cryolithozone.

Doom-roof steel tanks under external explosion: Dynamic responses and anti-explosion measures

Large-scale cylinder storage tank is a kind of typical thin shell space structure, which is widely used in the storage of petrochemical products such as LNG, LPG and so on. The dynamic responses and failure process for steel tank under external explosion shock wave are complex dynamic problems with strong instantaneity, strong non-linearity and strong coupling. In this paper, a coupled analysis model was developed for simulating the dynamic responses of tank under external ground explosion. Compared with experimental datas which were given in existing relevant studies, the validity for numerical model and accuracy for simulation results were verified. Dynamic response for typical cylindrical tank was obtained through coupled numerical simulation, and the influences of scaled distance and tank wall thickness were studied through parameter analysis. Based on the simplified model of explosion loading on tank, the difference of dynamic response between uncoupled model and coupled model was analyzed. The anti-explosion effect for different parameters of anti-explosion bands on tank under external explosion was finally compared. The results show that: 1) The lower two layers tank wall firstly appear inward concave deformation and local plastic state. With the shock wave propagating upward along tank wall, the concave deformation and plastic strain of the front surface of tank wall increase obviously, and the maximum deformation region moves up to the middle part of tank wall, while the maximum plastic region basically remains at the lower part of tank wall. 2) Both the changes of scaled distance and tank wall thickness have significant influences on the deformation and equivalent plastic strain for steel storage tank. The maximum equivalent plastic strain and fracture failure mode generally appears at the lower part of tank wall firstly. The increase of the tank wall thickness is an effective measure to reduce the deformation and plastic strain for tank, and strengthen the anti-explosion performance for tank. 3) Due to the obstacle effect of the anti-explosion bands, the maximum equivalent plastic strain region moves from the bottom part of tank wall to the middle and upper part of tank wall. The displacement and equivalent plastic strain for steel tank decrease with the increase of cross-section and spacing for anti-explosion bands, and the effect of the former (increase height only) is relatively better.

Экспериментальная оценка формирования взрывоопасной среды над плавающей крышей резервуара для хранения нефти в процессе откачки при пожаре соседнего резервуара

Introduction. The study of the formation of explosive concentrations of vapors of flammable liquids (hereinafter referred to as flammable liquids – LVL) in the gas space of a tank with a floating roof when pumping oil out of it during a fire of a neighboring tank in oil storage facilities in Vietnam. Goal and tasks. Consider the reasons for the spread of fire from a burning vertical, steel floating-roof oil storage tank (hereinafter – RVSPK) to an adjacent non-burning RVSPK with oil. Develop a program of experiments. Create an industrial experimental setup for measuring explosive and fire hazardous concentrations of light oil fractions above the floating roof of a full-scale reservoir with a volume of 65 000 m3 of crude oil. Conduct an experiment to measure the concentration of light fractions of oil over a floating roof during pumping. To experimentally determine the possibility of the formation of explosive and fire hazardous concentrations of light fractions of oil (methane), within the lower concentration limit of flame propagation, in the steam space above the floating roof of the RVSPK in real time in the process of lowering the level of the floating roof during pumping out oil in the event of a fire on a neighboring tank. Method. Analysis. Full-scale experiment. Results and discussion. A natural experiment was carried out. The results of studies on the distribution of concentrations of combustible vapors of light fractions of oil (methane) in the gas space above the floating roof of a non-combustible tank of 65000 m3 during oil pumping are obtained. The most probable places of formation of explosive concentrations are determined. To reduce the fire load, the risk of fire spread, possible damage and death caused by fire in large-capacity RVSPK oil storage facilities in Vietnam, it is proposed to pump oil from the adjacent RVSPK to the burning RVSPK in combination with concentration control in the aerodynamic shadow zone inside the RVSPK gas space. Conclusions. When crude oil is pumped out of the tank in the annular zone around the floating roof, an explosive methane-air mixture zone is formed with a methane concentration reaching the lower concentration limit of flame propagation. Keywords: fire, fire and explosion safety, reservoir, floating roof, concentration, combustion.

Reliability improvement of steel storage tanks for phosphoric acid

The paper describes the one-sided welding method for steel structures based on the rational choice of the inverse angle of butt-welded elements of Belgian steel for the manufacture of tank bottom elements of intended for phosphoric acid storage in a construction site. It is shown that the most expedient method for ensuring the design geometry of the tank with a minimum stress of 1.4507 of the material structure, is the bottom sheets preset for welding at a reverse angle of 12 degrees.The proposed method improves the tank reliability for storing aggressive products, its trouble-free and technical safety during the operation. The need is shown for studying the replacement of imported steel by Russian steel to manufacture tanks from alternative nonmetallic materials.

Design of Clean Steel Production with Hydrogen: Impact of Electricity System Composition

In Europe, electrification is considered a key option to obtain a cleaner production of steel at the same time as the electricity system production portfolio is expected to consist of an increasing share of varying renewable electricity (VRE) generation, mainly in the form of solar PV and wind power. We investigate cost-efficient designs of hydrogen-based steelmaking in electricity systems dominated by VRE. We develop and apply a linear cost-minimization model with an hourly time resolution, which determines cost-optimal operation and sizing of the units in hydrogen-based steelmaking including an electrolyser, direct reduction shaft, electric arc furnace, as well as storage for hydrogen and hot-briquetted iron pellets. We show that the electricity price following steelmaking leads to savings in running costs but to increased capital cost due to investments in the overcapacity of steel production units and storage units for hydrogen and hot-briquetted iron pellets. For two VRE-dominated regions, we show that the electricity price following steel production reduces the total steel production cost by 23% and 17%, respectively, as compared to continuous steel production at a constant level. We also show that the cost-optimal design of the steelmaking process is dependent upon the electricity system mix.

Characterization of Existing Steel Racks via Dynamic Identification

Steel storage racks are widely used in logistics for storing materials and goods. Rack design is carried out by adopting the so-called design-assisted-by-testing procedure. In particular, experimental analyses must be carried out by rack producers on the key structural components in order to adopt the design approach proposed for the more traditional carpentry frames. For existing racks, i.e., those in-service for decades, it is required to evaluate the load carrying capacity in accordance with the design provisions currently in use. The main problem in several cases should be the appraisal of the key component performance, owing to the impossibility to obtain specimens from in-service racks without reduction or interruption of the logistic flows. To overcome this problem, a quite innovative procedure for the identification of the structural unknowns of existing racks has been proposed in the paper. The method is based on in-situ modal identification tests combined with extensive numerical analyses. To develop the procedure, cheap measurement systems are required, and they could be immediately applied to existing racks. A real case study is discussed, showing the efficiency of the procedure in the evaluation of the effective elastic stiffness of beam-to-column joints and base plate connections, that are parameters which remarkably affect the rack performance. The structural unknowns have been determined based on four sets of modal tests (two configurations on the longitudinal direction and two in the transversal direction) plus 9079 iterative structural analyses. The results obtained were then directly compared with experimental component tests, showing differences lower than 9%.

Mine surveying technique and steel storage tank base deformation removal

Introduction. Vertical steel tanks are extensively used in oil fields to hold crude oil and other liquids. Their construction requires continuous surveying control. However, measurement procedures, data processing, and deviations and documentation correction are not universal and cannot be applied for tanks with a capacity of less than 3000 m3. Moreover, the process of correcting the detected bottom irregularities is poorly substantiated and intuitive. Research objective is to improve the as-built survey accuracy and reliability of the low-capacity steel tank bottom, substantiate the minimum height of its irregularities, increase the objectivity and productivity of measurement processing, develop an unambiguous method for time-predictable correction of bottom irregularities, and substantiate the optimal contents of its relief’s as-built scheme. Methods of research. Geometric leveling for the bottom profile survey failed to provide adequate accuracy and was therefore replaced by the method of trigonometric leveling. A method has been developed for determining the deviations of the existent tank bottom profile from the design position by means of algebraic actions with surfaces of a topographic order. The accuracy of determining the smallest height of bottom irregularities has been estimated under the tacheometric survey. A method has been proposed for controlling the correction of tank bottom irregularities based on evaluation calculations of bottom deformations by the finite element method. Research results. All the development results are exemplified by a specific production example. It was found that for a full completion of work, two iterations of tank bottom irregularities correction are enough. Methods of optimal design for the facility’s as-built schemes are presented. Conclusions. A simple, accurate, low-cost, productive, and time-predictable method of mine surveying, mathematical processing and correction of deviations in the tank bottom profile has been developed. This technique reduces the construction period and increases the operating time of the facility.

Effect of Bacillus megaterium Biofilm and its Metabolites at Various Concentration Biodiesel on the Corrosion of Carbon Steel Storage Tank

Microorganisms in biodiesel storage tanks may generate bio-corrosion due to their hygroscopic and susceptible fuel degradation. The organisms, including Bacillus megaterium present in the hydrocarbons, resulted from the EPS and metabolites processes that subsequently control the corrosion process of the tank. This present study examined the effect of biodiesel concentration on microbial activity through TPC analyzing growth for B. megaterium. Furthermore, this study investigated EPS formation and acid metabolites production by B. megaterium based on SEM observations and acidimetric titration. Meanwhile, this study investigated the microorganism-induced corrosion impact based on gravimetric analysis. The results explained a higher biodiesel concentration in diesel oil promoted an increase in the growth of B. megaterium and the corrosion rate. Conversely, the acid metabolites produced from bacteria under the biofilm did not significantly increase the corrosion rate. Corrosion products resulting from the B. megaterium activity on the surface of the steel included Iron (II, III) oxide (Fe2O3 and Fe3O4). The formation of oxide and pitting may control the strength of the surface tank in the course of biofuel storage, which may lead to the failure of the material.

On the seismic response of steel storage pallet racks with selective addition of bolted joints

Experimental tests on rack joints have shown that the cyclic response of beam-to-column joints, which in steel storage pallet racks is usually affected by pronounced pinching, could be significantly improved if joints are equipped with bolts. Bolts allow for ultimate moment, ductility, and dissipated energy of joints to be increased. Nevertheless, their installation in all joints of a rack system would be uneconomical and would nullify advantages of traditional boltless dry connections, which allow for beams to be easily disconnected if a new corridor or free space is required.The selective addition of bolted joints and its influence of the seismic response of rack systems is the focus of the manuscript. Different layouts of rack systems, with bolted connections only in some specific positions, are studied and compared. The addition of bolted connections improves the serviceability behavior, as the displacements of the system are reduced. Concerning the seismic capacity, the beneficial effect of bolted connections is appreciable only if seismic actions are sufficiently high and connections undergo plastic deformation. Configurations with bolted connections located only at the lowest levels allow to achieve a similar structural performance of a fully bolted configuration, saving the cost of the structure.

Torsional behaviour of thin‐walled members with regular perforation systems

AbstractThin‐walled cold‐formed (TWCF) steel members that are frequently used in steel storage rack systems generally present a monosymmetric cross‐section. The adopted design approaches derive strictly from those developed for the more traditional bisymmetric solid web members, despite i) the presence in rack components of the eccentricity between the shear center and the cross‐section centroid and ii) the regular perforation systems.The paper is addressed to the torsional response of TWCF members used for the vertical elements (uprights) in storage racks, which present regular perforation systems currently neglected in routine design. Attention is focused on the evaluation of the warping constant, which reflects directly in the distribution of the normal stresses associated with the bimoment. The approach considered by the future rack design code is discussed and a refined model based on the theory of elasticity is proposed to account for the sequence of solid and perforated cross‐sections along the longitudinal axis of the member. The proposed numerical applications are related to two different cross‐sections and the discussed research outcomes allow for an appraisal of the errors associated with a warping constant defined by neglecting the presence of regular perforation systems.