Tank Type Research Articles

Selection of equipment for oil tank repair in northern conditions

Introduction. The oil industry is a key component of the economy of the Russian Federation. A large number of tanks are used to store oil, each of which needs timely repair. According to the results of some research, almost half of the accidents are caused by excess uneven settlement of the tank, which causes premature failure. To restore the serviceable and operable condition of the tanks, it is necessary to carry out repair work, the quality and efficiency of which depends on the repair equipment used. An urgent task is to justify the choice of equipment for the repair of tanks, in particular, steel tanks of a vertical type.Methods and materials. A review of the different types of tanks was carried out and showed that vertical steel tanks are the most widely used. One of the ways to eliminate the uneven settlement of the tank is to raise it with the help of jacks and form a new base with the elimination of the slope.Results. The repair process for a 10,000 m3 steel vertical tank was considered. The values of the mass of the tank were obtained when filling with liquid petroleum products at 1% of the maximum occupancy. The value of the load on one lifting device is obtained. The design of the device structure and the strength calculation in the Compass 3D program were completed.Сonclusions. The most efficient type of the lift from the existing ones was determined, and its design was modernized. The strength calculation showed that the hydraulic lift is efficient under the given conditions.

Optimizing Tilapia Biofloc Technology Systems and Its Economic Profitability on Industrial Scale in Indonesia

One of the technologies that can produce a high number of fish in limited land and water is biofloc. Adapting biofloc technology in Indonesia from laboratory to industrial scale requires several improvements. This study aims to optimize biofloc technology and to reduce production costs. A series of research activities to increase the productivity of tilapia by biofloc technology have been carried out using superior seeds variety, proper application of stocking densities, type and volume of tank/pond, and the seed size at the stocking. Feed efficiency, productivity, survival rate, specific growth rate, and economic parameters were observed. Using tilapia superior seed can increase biomass by 4% compared to Nirwana II tilapia variety. The best seed density that can be used is 75-80 fish/m3, it is related to the appropriate type or volume of the round tank, which is 10 m3. The correlation value (R2) between the size of the initial seed and the observed parameters were 0.9439 (specific weight gain rate); 0.5841 (feed efficiency); 0.4880 (productivity) and 0.4789 (survival rate). Optimization of biofloc technology can save production costs up to 38.41 %. The value of the R/C ratio is 2.03.

Предотвращение каскадного развития пожара на тепловых электростанциях Вьетнама на основе применения резервуаров с защитной стенкой и волноотражающим козырьком

PURPOSE. The article, based on the results of an statistics analysis of vertical steel tanks (VST) destruction with flammable liquids, as well as forecasting the situation on the territory of a thermal power plant (TPP) during destruction of a typical VST-20 000 m3 with fuel oil, substantiates the need to use tanks with protective wall (TPW) and a wave-reflecting visor in tank farms at thermal power plants in Vietnam, as one of the promising methods aimed at preventing the possible cascading fire development at the facility or the occurrence of an emergency situation (ES). The main provisions of the method developed on the basis of performed experimental studies have been presented, which establishes the procedure for calculating the geometric parameters of a protective wall with a horizontal or inclined wave-reflecting visor, designed to completely contain the breakthrough wave during the quasi-instantaneous destruction of the main (internal) VST. METHODS. In the process of research methods of similarity theory and hydraulic laboratory modeling, physical experiment, observation, comparison, finding an empirical relationship based on mathematical processing of experimental data, description and generalization have been used. FINDINGS. The features of the location of thermal power plants in Vietnam have been revealed, consisting in their direct location in populated areas or near water bodies. It has been established that destruction of even one large-sized VST with flammable liquid in the tank farm of a thermal power plant can lead to a cascade development of an accident or emergency occurrence. It has been proven that installing a wave-reflecting visor on the protective wall is an effective way to reduce it to or below the maximum liquid level in the main VST, depending on the distance between the walls and the length of the visor extension. RESEARCH APPLICATION FIELD. The developed method, containing calculation schemes and empirical dependencies, can be the basis for the development of a regulatory document to ensure fire safety of TPW, including when they are located on the territory of tank farms of thermal power plants. CONCLUSIONS. The proposed design of the PWT, improved by installing a wave-reflecting visor, will make it possible to design and operate these types of tanks, ensuring the required level of fire, industrial and environmental safety at the protection site, subject to, among other things, the requirements for the stability of the wall and the visor to the effects of liquid flow and the main VST structures that collapse during an accident.

Understanding on-site sanitation in rural Fiji: where definitions of sanitation back-ends differ

This study assessed sanitation infrastructure and maintenance practices in rural Fijian communities. The high prevalence of tank type sanitation back-ends highlights the health and environmental risks.

Developing multi-objective optimization model with conflicting goals to improve the surge protection devices design for water hammer

In this study, a Multi-objective Optimization Model (MOM) is developed and solved for the optimum design of surge protection devices (including air chamber and shock damper) with conflicting goals. The shock damper is a new type of surge tank invented by researchers. For the first time, the design parameters of the shock damper as decision variables are raised in a MOM problem, and results are benchmarked with solving the model for the air chamber as well. Method of characteristics (MOC) is chosen for the numerical solution of water hammer PDE’s and its system of equations for interior and boundary nodes are used as constraints of the optimization model. The conflicting criteria of the MOM are functions of safety in the system and installation cost of protection devices. In the following by using the weight coefficients and normalized objective functions obtained by dividing each of the mentioned functions by the maximum potential values of them, the resulting problem is solved by Genetic Algorithm (GA). The results, while investigated conceptually, show the significant improvement of multi-objective design in the performance and cost-saving in protection devices and the better function of shock damper regarding both criteria.

Evaluation of mixing capability improvement of a circular water storage tank by nozzle system retrofit using computational fluid dynamics

ABSTRACT Studies on the mixing of water storage tanks typically consider vertically oriented nozzles, however, not much consideration was given for horizontally oriented nozzles. This paper aims to employ computational fluid dynamics (CFD) to study the influence of horizontal nozzle configurations on the mixing within a typical circular water storage tank. The impact of the outlet locations and water depths on mixing time was also investigated. The results from the numerical simulations show that nozzle configuration with horizontal distance between the sets of nozzles of 0.71 tank diameters apart performed the best. An outlet located in the center of the circular storage tank encourages near-floor lateral movement of fluid and improved the velocity uniformity across the water column. The water depth was found to have a non-monotonic relationship with the mixing time and the depth to diameter ratio of 0.4 provides the best mixing in the studied tank with nozzles.

Polypropylene module as a new type of tank for rainwater storage and cleaner production: Purification efficacy, bacterial community microecology and potential pathogens characteristics

Rainwater recycling is a hot issue in recent years, but polypropylene (PP) module as a new type of rainwater storage facility has not received extensive attention. This study investigated the impact of rainwater pollution level, storage time (ST) and operation mode (alternate replenishment of rainwater and reclaimed water) on the pollutants removal performance and bacterial community characteristics of PP module. Chemical oxygen demand (COD) removal efficiency increased from 24.58%–26.52% to 33.23%–42.23% with prolonged ST. Operation mode changed the purification performance, but the COD removal efficiencies in rainwater and reclaimed water were always above 28% and 42%, respectively. Operation mode exhibited the greatest impact on bacterial community structure, followed by rainwater quality and ST. The bacterial community classification in biofilm was different from that in water, but Klebsiella was always the dominant genus. Conditionally rare and abundant taxa (CRAT) and conditionally rare taxa (CRT) were identified as the hub taxa of biofilm-network and water-network, respectively. The potential pathogens in biofilm exhibited more complex interactions with non-pathogenic taxa than those in water. Klebsiella pneumoniae was the most dominant species and identified as the hub potential pathogen together with Escherichia coli in both networks. Bacterial communities in biofilm and water were significantly correlated with COD removal efficiency. These results elucidate the biological function and risk of PP module, and provide a reference for the optimization and operation management of the rainwater reuse system.

Research on assembly scheduling problem with nested operations

A two-stage assembly scheduling problem with nested operations (nASP) is proposed to minimise the bi-criteria of makespan and the specified average passage time (Pave) in the rocket tank welding workshop. The nASP's tanks are assembled utilising a variety of parts and machining techniques. Depending on the type of tank, there are different numbers of usable parts. Additionally, at the first stage, parallel available machines, operation-dependent setup times, unpredictable rework, and dynamic machining times are considered. Eight heuristics and two lower bounds are first developed, then a logistic-based improved genetic algorithm (LBIGA) is presented while considering the characteristics of the solutions. To further optimize the Pave while maintaining the makespan, a heuristic built on backward computations is also suggested. Then, utilising the offered algorithms as well as genetic algorithm (GA), Tabu search (TS), and variable neighbourhood search (VNS) from the literature, randomly generated instances of nASP are resolved and compared. Ultimately, the numerical trials show the viability and efficacy of the presented algorithms.

SEISMIC EVALUATION OF FLEXIBLE STEEL WATER STORAGE TANKS

Cylindrical steel liquid storage tanks are widely used for water supply and industrial chemicals. The seismic response of these tanks differs from buildings as it stores liquid with different hydrodynamic characteristics. Steel tanks can be exposed to severe damages during earthquakes such as elephant’s foot buckling, diamond shape buckling, roof damage and failure of anchor bolts. This research investigates the seismic behavior of flexible steel water storage tanks using an analytical method. A series of parametric analyses are conducted for a typical liquid storage tank with different geometry properties and soil conditions. The effects of storage tank height, wall thickness, and subsoil type are investigated and their effects on the seismic response of the tank are evaluated and discussed. The results indicate that the soil type (representing shear wave velocity and shear modulus of the soil) has a profound impact on the base shear, overturning moment and hoop stress in the flexible tanks.

Optimal design and operation of reverse osmosis seawater desalination system for boron removal with economic, energy, and environmental concerns

This paper introduces a superstructure-based simultaneous optimum design and operation of seawater reverse osmosis (RO) system with boron removal under time-variant constraints. Three operational strategies are utilized to improve operability of the system under boron restrictions, including changing the activated number of pressure vessels, permeates split ratio, and pH values. Moreover, exergo-environmental and exergo-econoenvironmental analysis models are integrated. The economic efficiency, energy utilization, and environmental impact could be optimized in both design and operation phases. The effect of water tank area, membrane type, and boron concentration on water production are investigated with constant feed conditions. Choosing proper water tank volume and type of membrane could not only reduce cost but also better operation conditions, such as improving the efficiency of pumps and reducing feed pH of RO pass 2. When both the eco-costs/value ratio and emergy rate of product are added as a penalty, the annual operation cost (a reduction of 5.50 %), emergy rate (a reduction of 7.02 %) and eco-costs/value ratio (a reduction of 7.48 %) of the product could be reduced with only a small amount of water cost increment (about 2.66 %). Improving the efficiency of pumps would be an effective method to improve overall performance of the RO plant.

Charging and discharging characterization of a novel combined sensible-latent heat thermal energy storage system by experimental investigations for medium temperature applications

Efficient and economical thermal energy storage (TES) system can effectively reduce the mismatch between seasonal energy supply and demand. The single tank type thermocline TES has been investigated as an economical alternative for medium temperature applications. However, key disadvantages of this design are quick degradation of thermocline thickness, thermal ratcheting and drop in temperature at outlet section during discharging. To overcome these issues, a new type of structured hybrid sensible-latent design is developed in this research. The focus of the present work is to experimentally investigate the charge and discharge performance of the proposed TES system and it is designed by incorporating the sensible heat concrete block with axial holes placed in between multilayers of PCMs (D- mannitol and adipic acid). Charge and discharge experiments are performed to study the effect of hybrid structured concrete and multilayer PCM's configuration on thermocline temperature profiles, stratification number, total energy stored and retained by the storage medium, effective charge and discharge efficiency and utilization ratio. The relative experimental study is developed for four configurations, i.e., multilayered sensible heat concrete with PCM (MLSPCM), two uni-layered sensible concrete with PCM (SLSPCM-1 and SLSPCM-2) arrangements and single sensible heat concrete block (SSCB) arrangement. The results show that the effective discharge efficiency and storage capacity of MLSPCM, SLSPCM-1, SLSPCM-2 and SSCB are 87 %, 85 %, 86 %, 79 % and 12.53kWhr, 10.37kWhr, 9.96kWhr, 6.23kWhr, respectively. Moreover, the charging and discharging behavior of MLSPCM is further characterized at different mass flow rates to study the effect on thermocline thickness formation, effective discharge time and amount of energy extracted from storage medium. The present study indicates that use of multilayers of PCM with suitable melting and solidification temperature together with low-cost sensible concrete, is a viable and economical TES solution for medium temperature applications.

Comparative study of the safety of two tugboats using new harmonized stability rules

Tugboat operations present a high degree of risk and to prevent accidents, the crew must know and manage very well all the necessary maneuvers. Stability is a critical aspect for the safety of tugboats and towing operations, so recently new international regulations have been developed. The tugboats perform several functions, the main one being pulling, but by being equipped with certain equipment and installations, the tugboats are intended for rescue, firefighting, depollution, ice breaking and occasional transport. For this study, two categories of tugboats were considered to determine the geometric characteristics, hydrostatic, of stability and longitudinal strength. The Modelmaker module is used to create the ship's body (Geometry File), the superstructure and all appendages, after which the compartmentation is created and the types of compartments and tanks are positioned in the ship's body. To determine the safety of the two tugboats from the point of view of stability, the heeling moment (the heeling arm) that occurs during towing with the righting arm was checked. At the end, the safety status of the two categories of tugboats was analyzed and new projects were proposed for the future, regarding the use of stability criteria for tugboats.

TECHNICAL AND ECONOMIC RATIONALE FOR THE USE OF TURBULA TYPE MACHINING MACHINES IN POLISHING THE SURFACE OF SMALL POLYMER POLYMERS

A method of wet polishing of polymer parts using a galvanizing machine with a complex spatial movement of the working tank type «Turbula» is proposed. According to the proposed method, the main stage of polishing the surface of the parts is carried out by abrasive ceramic bodies of complex geometric shape with the addition of fine pumice in the implementation of mixed cascade-waterfall mode of movement of the bulk working medium. This method of processing parts is considered highly productive, the processing time of parts averages 15 hours of continuous operation of the machine, which is several times faster than when processing parts in rotating drum drums or vibrating machines. The latter are characterized by low productivity of the relevant technological operations. The feasibility study of the method of wet polishing of polymer parts using a galvanizing machine with a complex spatial movement of the working capacity of the «Turbula» type for the implementation of the technological operation of polishing the surface of polyester buttons was performed analytically. The expected annual economic effect from the implementation of the developed method of wet polishing of polymer parts using a galvanizing machine with a complex spatial movement of the working capacity of the «Turbula» type, which will amount to UAH 14,059.8 per two units of equipment, is calculated. This method of processing can be used to improve the surface quality of any polymer parts with the possibility of achieving the appropriate value of the roughness of their surface. The obtained research results can be used in design bureaus of relevant enterprises for the manufacture of small polymer parts, the surface quality of which is determined by organoleptic method, as well as in design bureaus of machine-building enterprises specializing in the development of galvanizing equipment.

Sistem Pendukung Keputusan Pemilihan Hero Tank Mobile Legends Terbaik dengan Metode Moora

A properly made Decision Support System (DSS) will assist all communities in making effective and efficient decisions. Most people make SPK only as a recommendation for the best profession or students who have achievements, even though the DSS is very broad and can cover all aspects. Mobile Legends is a MOBA game with the Mobile genre that has many characters or heroes in the game which are divided into 6 types, one of which is the Tank type, but not all players, especially new players, know which heroes are suitable to play. Therefore, the need for an SPK for problems like this so that players don't get confused in choosing the Tank hero character and in this SPK later the user can enter any amount of data along with the value of each attribute. MOORA is one of the best methods used for DSS, MOORA has an uncomplicated calculation but produces recommendations from the best to the least recommended. Based on calculations, the best recommended Tank hero according to the Moora method is Khufra with a final value of 10.87841 while the non-recommended Tank hero is Hilda who has a final value of -2.4623.

Seismic vulnerability assessment of base isolated liquid storage tanks under near-fault ground motions

This paper aims to develop the fragility curves of base isolated liquid storage tanks under near-fault ground motions. Liquid storage tanks are important lifeline structures for industrial plants, but the damages from the past earthquakes showed their vulnerability. The seismic isolation technique is a promising approach to reduce the seismic demand in liquid storage tanks. It should be considered that near-fault ground motions can damage base-isolated liquid storage tanks due to their characteristics such as pulses in their time history velocity. Therefore, it is important to assess the vulnerability of the liquid storage tanks under near-fault ground motion. Fragility curves are useful tools for structural engineers to evaluate seismic performance of structures. In this study, two types of liquid storage tanks, i.e., broad and slender, are considered. The fragility curves for both non-isolated tanks and base-isolated tanks by Friction Pendulum System are developed and compared. Six failure criteria have been considered for the fragility curves, including vertical displacement of convective mass, elastic buckling of tank wall, yielding of anchorages, elephant foot buckling, pipe-line fracture and base isolation displacement. Furthermore, the effect of the isolation period and the coefficient of friction on the fragility curves are investigated. The results show that the pipeline fracture and the tank’s wall buckling are the two most important parameters, which govern the behaviour of liquid storage tanks.

Hydrogen gas dispersion studies for hydrogen fuel cell vessels I: Vent Mast releases

We report modeling results for hydrogen releases associated with deploying hydrogen fuel cell technology on vessels. This first paper (I) considers hydrogen releases through the vessel Vent Mast from 250-bar hydrogen gas storage tanks, the type of tanks being used for the first hydrogen vessels. A manifolded 10-tank hydrogen storage system, holding 278 kg of hydrogen, can be emptied in ∼10 min for maintenance purposes, with a pressure reduction to half the original pressure (125 bar) realized in 2 min if a rapid pressure reduction is needed, for example in the event of a fire. The time profile for filling a tank is also of interest so as not to exceed the tank thermal limits. The calculations show that a manifolded 10-tank array can be filled with hydrogen to 250-bar pressure in ∼2 h from a 350-bar hydrogen refueling trailer without exceeding the 85 °C temperature limit typical of Type IV hydrogen tanks.Computational fluid dynamic (CFD) modeling shows that when the hydrogen is released out of the 10-tank array and into the Vent Mast in a 5-mph wind blowing horizontally, the effect of the wind on the hydrogen dispersion strongly depends on the hydrogen exit speed. For high release speeds (∼800–900 m/s), the hydrogen flow is strongly momentum-driven, and there is modest cross-wind influence. For low hydrogen exit speeds (∼10 m/s), the hydrogen is readily entrained in the wind flow and blown sideways, with the downstream flammable envelope rising at a positive angle to the horizontal due to buoyancy. To capture the influence of a wind with a downward component (e.g., created by a downdraft near a building), a calculation of a low-velocity (8.6 m/s) hydrogen release was performed with a 5-mph wind pointed downward at a 45° angle. The results show that despite the buoyancy of hydrogen, the wind blows the hydrogen substantially downward for low hydrogen speeds exiting the Vent Mast.

Implementasi Algoritma K-Means untuk Menganalisa Pemain Video Game Mobile Legend untuk Mengetahui Tipe Hero dan Role yang Sering Digunakan pada Setiap Kalangan

Video games are one of the technologies in the entertainment field that are growing rapidly in the community. Even Esports (video game competitions) are increasingly recognized by the industry as a recreational sport. An example of an esport that is currently popular among people is Mobile Legends. Both Android and IOS smartphones can run the Mobile Legends video game application. However, no one has ever discussed using the developer's built-in Role-playing as an alternative hero to simplify the Role-playing combination guide in the game, grouping characters according to their characteristics, and using characters according to the player's wishes. For this reason, this study uses the k-means algorithm to compile the grouping of heroes and Role-playing in the Mobile Legend video game. From the results of the research conducted, there are three groups of heroes that have similar characteristics, namely Mage, Marksman, and Fighter. The K-Means algorithm used can help determine the order of hero launches. Based on the results of clustering testing using the K-Means method, data in cluster 1 was obtained with an average accuracy of 5% hero support; heroes Tanks 10%; Fighter heroes 20%; hero Mage 25%; hero Assassin 20%; Marksman heroes 20%; then for the average age of 25.1 ; win rate 67.3; total matches 5863.4 and total MVP 1664,1. Players with hero support, tank, fighter and mage types have Roles as supporting tools to develop a core Role or Marksman and assassin heroes who have high capabilities as winners in the team, with an average user who has a supporting Role of 0.15 and an average user with 0.2 . Role core

Preliminary Study on Deformation During Hydrostatic Testing in a Deep Tank

There are many different types of tanks on ships that meet various requirements. Each tank is required to undergo hydrostatic testing according to the Ship Safety Act after being installed onboard. In some hydrostatic tests, excessive deformation may occur. The overpressure of the air in the tank generated during testing is one of the possible causes of deformation. Based on the dimensions of the tank, nozzle, and pipes installed, it was confirmed that the overpressure of the air can cause problems with the structure, according to the Bernoulli equation. Additionally, finite element analysis (FEA) was performed on the tank structure to confirm the deformation and the stress occurring in the structure. From the perspective of deformation, the maximum deflection limit was set based on the criteria provided by the Eurocode and DNV. From the perspective of stress, the structural safety assessment was performed by comparing the allowable stress and equivalent stress generated in the structure. To determine whether the behavior of the actual structure was well implemented via FEA, beam theory was applied to the tank structure and compared with the FEA results. As a result of the analysis, severe deformation was found in some cases. This means that the overpressure of the air may be the cause of actual deformation. It was also confirmed that permanent deformation may occur.

A Novel Approach to the Improvement of the Hydropower Plants Protective Measures—Modelling and Numerical Analyses of the Semi-Pneumatic Surge Tank

Adopting adequate operational and safety measures is a significant part of the investigation of transient processes of hydropower plants (HPPs), both throughout the design stage of prospective plants and throughout the planning stage of the HPPs envisaged for refurbishment/uprating. One of the surge tank (ST) types, insufficiently researched so far, with a potential positive techno-economical influence, is the semi-pneumatic surge tank (SPST). Since the detailed analyses of SPST have never been performed or published before, the SPSTs have been examined here by presenting theoretical considerations, a newly developed mathematical model and comprehensive numerical simulations. The aim is to improve the performance of the open-air variations of STs. Multiple numerical simulations for a specific case-study HPP have been performed with the conclusions about the peculiarities and benefits of the SPST implementation. Firstly, numerical results for the existing as-built surge tank and corresponding alternative SPST have been compared, in order to verify the developed model. Variations of the main SPST constructive parameters have been analyzed, with the aim to determine the sensitivity of particular influences on transient processes versus its geometry alterations. The conducted analyses show that the SPST application brings HPP transient behaviour improvement compared to open-air ST. Dimensions of the new surge tank with specific aeration orifice could be smaller than the ones previously defined: both the diameter of the optimized upper and lower chamber and the core could be decreased by 20% and 12.5%, respectively.

Влияние наклона волноотражающего козырька на высоту защитной стенки резервуара типа «стакан в стакане»

PURPOSE. The article presents the results of experimental studies analysis on the influence of horizontal and inclined wave-reflecting visors proposed for installation on the protective wall of glass-in-glass tank type for reducing its height to or below the maximum possible level of liquid in the main tank. METHODS. In the process of the research work methods of similarity theory and hydraulic laboratory modeling, physical experiment, observation, comparison, finding empirical dependence based on mathematical processing of experimental data, description and generalization have been used. FINDINGS. It has been found that fitting a horizontal or inclined wave-reflecting visor on the protective wall of a “glass-in-glass” type tank is an effective method of reducing its height. At the same time, the best results are shown by a wave-reflecting visor at an angle of 135° to the protective wall which allows, in the interwalled distance ranged from 1.8 to 3 m given the length of its handling radius reducing the height of the protective wall to 85 % of the maximum possible level of liquid in the main tank. RESEARCH APPLICATION FIELD. The proposed method of reducing the height of the protective wall, design schemes and empirical dependencies can serve as the foundation for the development of a regulatory document on ensuring fire safety of “glass-in-glass” type tanks, as well as be used by design organizations to find optimal solutions for the design and placement of typical tanks with a nominal volume of 700 to 30.000 m3. CONCLUSIONS. The proposed design solution will allow designing and operating “glass-in-glass” type tanks, ensuring the required level of fire, industrial and environmental safety provided compliance with the requirements for stability of the protective wall and wave-reflecting visor to the effect liquid flow and collapsing structures in case of the accident of the main tank. At the same time, the application of an additional barrier is not required, since all liquid in case of possible destruction of the main tank will be held by the proposed structure of the protective wall with a wave-reflecting visor.