scholarly journals Effect of settlement of foundations on the failure risk of the bottom of cylindrical steel vertical tanks for liquids

2019 ◽  
Vol 41 (3) ◽  
pp. 171-176 ◽  
Author(s):  
Eugeniusz Hotala ◽  
Rajmund Ignatowicz
Keyword(s):  
The State ◽  
Numerical Analyses ◽  
Storage Tanks ◽  
Steel Sheets ◽  
Failure Risk ◽  
Different Types ◽  
Steel Tank ◽  
Soil Settlement ◽  
Tank Bottom ◽  
Cylindrical Steel

AbstractDifferent types of foundations are used in steel, above-ground cylindrical storage tanks for liquids. If a sand-gravel foundation is used under the entire bottom of the tank or only in the central part of the tank, settlement can be expected, and it increases after many years of operation. The paper presents the typical kinds and types of soil settlements under the bottoms of the tanks, in which different types of foundations were used. Numerical analyses of the effect of the soil settlement on the state of deformations and stresses in steel sheets of the bottom under one of the real tanks, in which different types of foundations and different cases of settlement were assumed. The results of numerical analyses indicated the possibility of evaluating the state of the soil settlement and bottom sheet deformations on the basis of simple measurements of deformations of the lower part of the tank cylinder. These measurements can be very useful in assessing the possible risk of failure of the tank bottom during each period of its operation, as measurements of settlement of the bottom of a filled tank are not feasible in practice. It has been proposed that in each steel tank, the deformation of the cylinder’s sheets should be measured even before the beginning of exploitation, and that in subsequent periodical measurements, the influence of the soil settlement under the tank on the state of the cylinder deformation and bottom’s strain should be assessed more accurately.

SEISMIC RESISTANT DESIGN OF CYLINDRICAL LIQUID STORAGE TANKS

1981 ◽  
pp. 77
Author(s):  
Vitelmo Bertero
Keyword(s):  
Seismic Behavior ◽  
State Of The Art ◽  
The State ◽  
Experimental Investigations ◽  
Future Research ◽  
Storage Tanks ◽  
Liquid Storage ◽  
Different Types ◽  
Seismic Resistant ◽  
Recent Earthquakes

This is a paper that summarizes the state of the practice and state of the art in the prediction of seismic behavior of cylindrical liquid storage tanks. It can be divided into five parts. In the first part the seismic performance of these types of tanks during recent   earthquakes is brielfly reviewed. From this review it becomes evident that a large percentage of these tanks have failed or suffered severe damages. The different types of failure are classified into several categories. The second part of the paper discusses the desing of some of the thank that suffered damages andthe state of the practice is summarized by reviewing present seismic code desing provisions. Thirdly, the soundness of these code provisions is analyzed in view of the state of thank.  Results obtained in recent theoretical and experimental investigations of such behavior are summarized and implications regarding needed improvement in seismic desing are assessed. Results from analyses of an existing  thank using different methods are presented and compared. An improved procedure for the practical seismic resistant desing of these thanks is outlined in the fourth part of the paper. A series of practical desing rules which provide extra margins of safety are offered and the extra cost required is discussed. Finally, recommendations for future research to improve the desing and construction of this type of liquid storage thanks are formuated.

Laboratory formation of border ice and frazil slush

1977 ◽  
Vol 4 (2) ◽  
pp. 153-160 ◽  
Author(s):  
T. O'D. Hanley ◽  
B. Michel
Keyword(s):  
Room Temperature ◽  
Variable Speed ◽  
Water Ice ◽  
Air Temperatures ◽  
Cold Room ◽  
Rate Of Increase ◽  
Steel Tank ◽  
Cylindrical Steel ◽  
Variable Speed Motor ◽  
Water Speed

Ice formation under controlled conditions was studied in a cold room using a cylindrical steel tank 120 cm in diameter and 76 cm deep. Paddles turned by a variable speed motor moved the water about the axis of the tank. Twenty-one thermistors were used to record temperatures above and below the surface of the water. Ice was allowed to form with the cold room temperature held at −2 °C, −5 °C, −10 °C, and −20 °C and with water speeds (measured 4 cm from the tank wall) from 0 to 73 cm/s.At zero water speed ice formed first as needles randomly oriented over the surface. With flowing water, border ice width increased linearly with time, but independently of water speed. The rate of increase of the border width w fits the equation dw/dt = (4/9)|Ta|0.68 where Ta is the Celsius air temperature.Frazil was never observed at water speeds less than 24 cm/s, but was always formed at this or greater speeds, regardless of cold room temperature. The volume of slush accumulated was greater at greater water speeds and at colder air temperatures. Observed slush volumes are compared with semiempirical values of the ice mass obtained from theoretical equations. The data suggest that growth of ice crystals began when the water was supercooled by approximately 0.02 °C.

Sloshing Response of Floating Roofed Liquid Storage Tanks Subjected to Earthquakes of Different Types

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
F. G. Golzar ◽  
R. Shabani ◽  
S. Tariverdilo ◽  
G. Rezazadeh
Keyword(s):  
Ground Motions ◽  
Far Field ◽  
Storage Tanks ◽  
Natural Period ◽  
Design Spectrum ◽  
Long Period ◽  
Lateral Forces ◽  
Different Types ◽  
Hamiltonian Variational Principle ◽  
Stress Patterns

Using extended Hamiltonian variational principle, the governing equations for sloshing response of floating roofed storage tanks are derived. The response of the floating roofed storage tanks is evaluated for different types of ground motions, including near-source and long-period far-field records. Besides comparing the response of the roofed and unroofed tanks, the effect of different ground motions on the wave elevation, lateral forces, and overturning moments induced on the tank is investigated. It is concluded that the dimensionless sloshing heights for the roofed tanks are solely a function of their first natural period. Also it is shown that while long-period far-field ground motions control the free board height, near-source records give higher values for lateral forces and overturning moments induced on the tank. This means that same design spectrum could not be used to evaluate the free board and lateral forces in the seismic design of storage tanks. Finally, two cases are studied to reveal the stress patterns caused by different earthquakes.

Atomization of Liquids by Means of a Rotating Cup

1950 ◽  
Vol 17 (2) ◽  
pp. 145-153 ◽  
Author(s):  
J. O. Hinze ◽  
H. Milborn
Keyword(s):  
Working Conditions ◽  
Drop Size ◽  
Film Formation ◽  
Angular Speed ◽  
The State ◽  
Experimental Results ◽  
Drop Formation ◽  
Dimensionless Groups ◽  
Different Types ◽  
Centrifugal Action

Abstract Liquid, supplied through a stationary tube to the inner part of a rotating cup widening toward a brim, flows viscously in a thin layer toward this brim and is then flung off, all by centrifugal action. The flow within this layer and the disintegration phenomena occurring beyond the brim have been studied, experimentally as well as theoretically. A formula has been derived for the thickness and for the radial velocity of the liquid layer within the cup, which proved to agree reasonably well with experimental results. Three essentially different types of disintegration may take place around and beyond the edge of the cup designated, respectively, by: (a) the state of direct drop formation; (b) the state of ligament formation; and (c) the state of film formation. Which one of these is realized depends upon working conditions. Transition from state (a) into (b), or of state (b) into state (c) is promoted by an increased quantity of supply, an increased angular speed, a decreased diameter of the cup, an increased density, an increased viscosity, and a decreased surface tension of the liquid. The experimental results have been expressed in relationships between relevant dimensionless groups. For the state of ligament formation a semiempirical relationship has been derived between the number of ligaments and dimensionless groups determining the working conditions of the cup. Results of drop-size measurements made for the state of ligament formation as well as for the state of film formation show that atomization by mere rotation of the cup is much more uniform than commonly achieved with pressure atomizers.

Tanks Assurance and Endorsement Extension Strategy

2021 ◽  
Author(s):  
Sahar Abdul-Karim Khattab ◽  
Marwa Sami Alsheebani
Keyword(s):  
Corrosion Protection ◽  
Oil And Gas ◽  
Extended Period ◽  
Oil And Gas Industry ◽  
Corrosion Monitoring ◽  
Storage Tanks ◽  
Major Overhaul ◽  
Gas Industry ◽  
Future Challenges ◽  
Tank Bottom

Abstract The objective of this paper is to study various methods that can be implemented on existing or new tanks to achieve an extended endorsement period (e.g. 20 years plus) for Crude Oil Floating Roof Storage Tanks. This extended period is necessary in order to overcome anticipated future challenges in tank availability due to (i) increased production and loading, (ii) stretched major overhaul (MOH) duration due to unforeseen delays in MOH works, (iii) corrosion in bottom plates, etc. An extensive research based on international API Standard 653 "Tank Inspection, Repair, Alteration, and Reconstruction" was conducted to achieve this extended period. Initially, some COS tanks aspects were assessed based on API SPEC 653 (2014, Addendum 2, May 2020) to achieve this new Tanks Endorsement Vision, such as: (a) studying the currently applied Corrosion Protection Barriers to the COS tanks and their effectiveness to the endorsement period, (b) the adequacy of commonly applied Corrosion Protection Barriers with respect to the endorsement period, and (c) exploring possible enhancements on COS Tanks Corrosion Protection Barriers, and Monitoring systems to extend tanks endorsement period. Based on API SPEC 653 (2014, Addendum 2, May 2020), currently applied tank safeguards were found inadequate to achieve the 20 years plus tank endorsement period requirement. In order to extend tanks endorsement period, additional safeguards shall be implemented, with special attention to tank bottom plates (soil side), since corrosion problems are mostly exhibited in tank bottom plates from the soil/oil side. Multiple solutions for corrosion safeguards were explored and recommended as part of this study such as the installation of a CP system under COS tanks, as well as installation of a corrosion monitoring system, and performing routine in-service inspections for COS tanks (internal and external) as per API SPEC 653 (2014, Addendum 2, May 2020), etc. Overall, this paper provides an insight on the calculation method of tanks endorsement period, and possible tank corrosion safeguards and controls that can be implemented to extend the COS tanks endorsement period to at least 20 years. Results and recommendations studied in this paper will benefit the Oil and Gas Industry and help in overcoming future challenges.

Differential Multipliers for Tourism in Victoria

1997 ◽  
Vol 3 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Guy R. West ◽  
Ari Gamage
Keyword(s):  
Economic Impacts ◽  
Value Added ◽  
The State ◽  
Input Output ◽  
Relative Contribution ◽  
State Economy ◽  
Different Types

This study assesses the significance of different types of tourists to Victoria, Australia, by their relative contribution to the economy. Differential impacts are calculated using an input–output model incorporating marginal household coefficients. The analysis demonstrates that the conventional input–output model can overestimate the flow-on effects to value added, income and employment by a significant amount. It finds that domestic tourists are the largest contributor to the State economy, with day-trippers spending the greatest amount. International tourists rank last in terms of economic impacts on the state.

Inside global financial networks

2018 ◽  
Vol 8 (3) ◽  
pp. 294-299 ◽  
Author(s):  
Laura-Marie Töpfer
Keyword(s):  
Firm Behavior ◽  
Financial System ◽  
The State ◽  
Financial Networks ◽  
Different Types ◽  
Competitive Hierarchies ◽  
Global Financial System

The commentaries on this forum’s anchor article, ‘China’s Integration into the Global Financial System: Toward a State-led Conception of Global Financial Networks’, examine how the state is shaping global financial networks (GFNs). In response to these reviews, this article discusses three common themes that bind the different commentaries: (1) different types of agency, power, and the rise of new actors; (2) the methodology behind studying state-led GFNs; and (3) the structural question of ‘Chinese exceptionalism’ as a mode of capitalism. Overall, this article affirms that the state remains central to our understanding of competitive hierarchies and firm behavior in financial networks.

scholarly journals Mine surveying technique and steel storage tank base deformation removal

2021 ◽  
Vol 1 (7) ◽  
pp. 69-79
Author(s):  
Aleksandr I. Barulin ◽  
Keyword(s):  
Low Cost ◽  
Operating Time ◽  
Construction Period ◽  
Steel Tank ◽  
Steel Tanks ◽  
Algebraic Actions ◽  
Minimum Height ◽  
Survey Accuracy ◽  
Tank Bottom ◽  
Mine Surveying

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.

scholarly journals Activated Flooded Jets and Immiscible Layer Technology Help to Remove and Prevent the Formation of Bottom Sediments in the Oil Storage Tanks

2021 ◽  
Author(s):  
Georgii V. Nesyn
Keyword(s):  
Crude Oil ◽  
Bottom Sediments ◽  
External Heat ◽  
Storage Tanks ◽  
High Molecular Weight Polymer ◽  
Molecular Weight Polymer ◽  
Oil Storage ◽  
Screw Propeller ◽  
Fit For Purpose ◽  
Tank Bottom

Two flooded jet methods of tank bottom sediments caving based on either screw propeller generation or nozzle jets generated with entering crude head oppose each other. The comparison is not advantageous for the first one. Exceptionally if crude oil contains some concentration of high molecular weight polymer which can perform Drag Reduction. In this case, the jet range increases by many times, thus, upgrading the capability of caving system. Preventing the sedimentation of crude oil heavy components may be put into practice with Immiscible Layer Technology. Before filling the tank with crude oil, some quantity of heavy liquid, that is immiscible with all the components of crude oil, is poured into the tank. The most suitable/fit for purpose and available liquid is glycerin. Neither paraffin and resins, nor asphaltenes can penetrate through the glycerin layer to settle down at the tank bottom because of its density, which is equal to 1.26 g/cm3. Instead, sediments are concentrated at/on the glycerin surface and when it is heated in external heat exchanger all the sediments ought to move upwards with the convection streams. Thus, no deteriorate sediment is formed in the tank bottom.

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