Large Tank Research Articles

Experimental and numerical analysis of the chill-down process of a large horizontal cryogenic storage tank

An experimental system is built to investigate the chill-down process of a 60 m3 horizontal cryogenic storage tank. Accordingly, a numerical model of the chill-down process is constructed to calculate the two-phase flow transition and thermal stress distribution. The chill-down processes with flow rates of 35 L/min and 43 L/min are investigated. The results show that the chill-down process of the wall can be divided into three stages, including slow cooling by cryogenic gaseous nitrogen, rapid cooling by boiling liquid nitrogen, and conduction cooling in contact with liquid nitrogen. Moreover, the maximum deformation in horizontal tanks shifts from the middle to the end of the bottom due to the uneven temperature variation during the chill-down process. The study highlights a positive correlation between the temperature gradient and the stress value. As the liquid accumulates, a large circumferential stress appears at the liquid level, resulting in the maximum stress section at the same height as the liquid level. The maximum stress except the constraint is about 248 MPa at a flow rate of 43 L/min. Overall, the analysis of the experimental and simulation results in this work provides useful information and guidance for the safe use of large horizontal cryogenic storage tanks.

Effect of Jet Nozzle Position on Mixing Time in Large Tanks

The present investigation focuses on the impact of jet nozzle orientation on mixing time in a cylindrical tank. The aim is to identify nozzle positions that improve mixing performance and to elucidate the governing parameters that influence it. A water tank was employed for the experiment. The vertical inclination angle (α) and the horizontal inclination angle (β) of the jet nozzle determined the nozzle positions. Mixing time was determined using an inert tracer and spectrophotometry measurements. The findings show that the mixing time is significantly influenced by the position of the jet nozzle position. The accuracy of existing jet turbulence and the circulation models for the prediction of mixing time was evaluated for the different nozzle positions. Our results indicate that both models provide accurate predictions for the conventional centrally aligned (β = 0°), upward-pointing jet nozzle positions only (α > 0). For the other nozzle positions where β > 0° and at varying α, the data follow the same trends as the jet turbulence and circulation models; however, the proportionality constants vary. Shorter mixing times can be attributed principally to longer jet path lengths and therefore higher fluid entrainment and circulation as well as higher dissipation rates per jet length squared. However, it is suspected that the three-dimensional nature of the flow pattern generated in the tank also plays a non-negligible role since mixing is hindered when the nozzle points more towards the tank wall.

A multi-zone thermodynamic model for predicting LNG ageing in large cryogenic tanks

During the storage and transportation of liquefied natural gas (LNG), generation of boiloff gas (BOG) and change in the LNG composition, also known as LNG aging, are inevitable. Thus, a thermodynamic model that can accurately predict LNG aging during long-term operation is critical. This study presents a novel aging model, in which the LNG tank is divided into five zones: the vapor phase region, thermal stratification, bulk liquid region, boundary layer, and surrounding thermal insulation region. The heat and mass transport into different regions were calculated separately, and the thermal conductivity of the solid walls was considered as a function of temperature. Following model validation, simulations were performed for various thermal insulation conditions, ambient temperatures, and initial liquid compositions. From the results, the errors of the pressure, BOG rate and total heat flux could be approximated to 17, 7, and 14% respectively, for the previous models omitting the variation of thermal conductivity with temperature. As the initial methane fraction increased (i.e., N fraction decreases), the BOG rate decreased at the initial stage, while the BOG rate became less sensitive with the initial LNG composition as evaporation proceeded. Such an effect is determined by the variation in the latent heat of vaporization and total heat loss. This study can provide guidance for the design and operation of LNG storage tanks.

Continuous cold ethanol precipitation of immunoglobulin G from human plasma

Currently intravenous immunoglobulin G (IVIG) is manufactured by cold ethanol precipitation in batch, which results in a slow process with a high footprint due to the use of large tanks. A batch precipitation method using ethanol for the production of IVIG from “cryo-poor plasma”, a starting material obtained after removal of cryoprecipitate from thawed fresh frozen plasma was rendered into a continuous method using a tubular reactor. This reactor consisted of double jacketed stainless-steel tubes filled with static mixers for efficient cooling, because the heat transfer in stainless steel is very high. The pH adjusted, precooled plasma and ethanol were fed into a tubular reactor and cooled down to − 7 °C and precipitation was induced and completed after having left the reactor. The precipitate at the reactor effluent was harvested by tandem precoat filtration or pseudo continuous batch centrifugation. Yield and purity were in the same range as the batch precipitation method, with 95% yield. Even with a residence time of one minute, complete precipitation with same yield and purity could be achieved. A tubular reactor with a length of 3.5 m and 3.7 cm internal diameter would be suited to process 4000 L of plasma per day. This concept will be the basis to substantially shrink the plant footprint of new plants or be a way to intensify existing manufacturing plants.

Tank Jet Mixer Design, Arrangement & Applications

Side entry mixers or jet mixers are commonly used to achieve mixing in storage tanks and reactors. Impellers are other conventional devices used for mixing in industry, but they are expensive for large storage tanks and underground tanks. Jet mixers have been a better alternative to impellers in the process industry. Compared with Mechanically agitated mixers, these mixers use jet technique to create high turbulence, high shear rates and vortex motion offer several advantages in achieving rapid mixing over a short period of time without any moving parts. Jet mixing has become an alternative to conventional impeller mixing for various applications in process industries. To ensure optimal mixing performance, it is important to understand the basis of jet mixer design & also impact of different parameters in jet mixer design & preferred installation of mixers.

The Use of Augmented Reality for the Management of Equipment Ageing with a Virtual Sensor

Much of the equipment that is used in the chemical and process industry and for handling or treating hazardous substances is subject to deterioration. To manage the risk of major accidents due to this deterioration, the current legislation requires periodic controls that must be carried out to verify the health conditions (ageing). To support the inspectors performing this task, a virtual sensor has been designed and developed. It is a system composed of hardware and software that uses mathematical models and augmented reality to assist in on-field inspections for monitoring and predicting equipment ageing. Currently, there are no AR devices to perform inspections aimed at verifying the integrity of equipment. The virtual sensor collects ageing-related information and returns the corrosion rate, the probability of the critical pit, the corrosion evolution through iso-contour corrosion maps, and the RUL; finally, it allows visualising the equipment condition through augmented reality, (e.g., by means of thickness maps and tables that overlay the equipment). The aim of this paper is to present the graphical interface of the software application, which has been improved to minimise errors due to human–machine interaction. A large diesel storage tank has been used to show how the virtual sensor works.

Insulated concrete form foundation wall as solar thermal energy storage for Cold-Climate building heating system

Employing green energies for building energy sector decarbonization has captured the world’s attention in the current century. However, the imbalance between energy demand and availability necessitates designing reliable and cost-effective energy storage systems. The present study aims to propose an innovative building-integrated solar thermal storage method using insulated concrete form (ICF) foundation walls for residential buildings in cold climates such as that of Canada. Surplus solar thermal energy is stored inside the ICF wall, which has a high thermal capacity and mass and is integrated into the building envelope. The ICF wall and solar thermal collectors are coupled with a water-to-water heat pump to meet building space heating load and domestic hot water demand. Different configurations integrating the ICF wall are modeled and simulated in TRNSYS software to perform a yearly transient analysis. It is shown that a system with ICF walls has an 11% higher solar fraction (SF) than a similar system with a large water thermal storage tank. By replacing the solar thermal collector with a hybrid photovoltaic/thermal collector, the overall system solar fraction can increase to 20% above that of a similar system with a large water thermal storage tank system. An ICF-based system with a 16 m2 solar collector can completely cover nine months of space heating and domestic hot water load for a single-family house in London, Ontario. A detailed sensitivity analysis shows that the proposed ICF-based systems achieve an optimum solar fraction at high tilt angles (65-70°), unlike a similar design with an extensive water thermal storage tank system. Because of their ability to achieve a high SF at high tilt angles, ICF systems are suitable for vertically mounted solar systems typically required by high-rise buildings due to limited roof area. As part of the building envelope, ICF foundation walls have no additional cost and can be considered a feasible strategy for reducing the residential sector’s carbon footprint..

Insights from the judgment bias paradigm: Social group and tank size does not affect mental state in female guppies.

Optimal holding conditions are key to animal welfare. How stressful husbandry is perceived by the animal can be determined via assessment of an animal's mental state - where it is positioned on the continuum between optimistic and pessimistic state - and can be measured using the judgment bias paradigm. In this test, individuals are trained to distinguish a rewarded from an unrewarded cue before being presented an ambiguous, intermediate cue. The response time to the ambiguous cue is then indicative of mental state. A shorter latency suggests a more positive (optimistic) mental state, a longer latency a more negative (pessimistic) mental state. Here, we used the judgment bias paradigm to assess the impact of standard laboratory housing conditions on the mental states of female guppies (Poecilia reticulata). As it is debated which holding conditions confer optimal welfare, we tested the impact of husbandry on mental state by keeping animals for three weeks in small or large social groups in either small or large tanks. We found that the different standard housing conditions we used did not lead to differences in mental state. As an unexpected side result, we found that female guppies seem lateral. Our findings of comparable mental state across housing conditions suggest that guppies either perceive the tested conditions as equally stressful or alternatively, that guppies are relatively resilient to the combination of group and tank sizes tested in this study. We conclude that the judgment bias paradigm can be a useful tool to assess fish welfare. This article is protected by copyright. All rights reserved.

An intermediate water gravity wavelength and wave height measurement inside a large wave flume tank

This paper discusses an intermediate water gravity wavelength and wave height measurement method. Three methods were used to obtain wave height, wavelength, and period. Firstly, conventional methods used two Honeywell pressure sensors mounted at the bottom of the wave tank at two different locations. Secondly, using the transfer function of the flap wavemaker (the relationship between wave height and the wave paddle stroke). Thirdly, the Laser Sheet technique (PIV image processing technique). The significant wave height and period from pressure reading sensors of regular gravity waves were obtained from the Raleigh distribution and Zero up crossing technique. Wavelength was obtained indirectly by using a dispersion relationship that was solved by using the Newton Raphson numerical method from both the pressure sensors and the transfer function of the flap wavemaker. This experiment was focused on getting the direct value of wave measurements by developing an image processing technique in a clear large wave flume tank to replace the conventional methods and eliminate the error that may produce by using the numerical methods. The PIV setup with the CCD camera was used to capture wave images. The image processing technique based on Canny edge detection with constant threshold value was used to detect the edge of the waves. The experimental result showed a good agreement between the results obtained from these three methods, with the percent of error up to 8.683%.

Design and Optimization of the Insulation Performance of a 4000 m3 Liquid Hydrogen Spherical Tank

Efficient insulation technology is one of the key technologies for the development of large LH2 storage tanks. This paper aimed at a 4000 m3 LH2 spherical tank, many insulation schemes were designed, including multilayer insulation systems integrated with a vapor-cooled shield (VCS) and liquid-nitrogen-cooled shield (LN2CS). The heat transfer model was developed to predict the insulation performance of a LH2 spherical tank. The effect of the VCS position on insulation performance was studied, and the different configurations of double VCSs were compared and discussed. The results showed that the daily evaporation rate of MLI, hollow glass microspheres (HGMs) and vacuum was only 2.05 × 10−3%, 3.62 × 10−3% and 7.94 × 10−2% at 1.34 Pa, respectively. MLI was still the optimal insulation scheme for a 4000 m3 LH2 spherical tank. Meanwhile, it was found that when the single VCS was placed at the 10th layer, the heat leakage was reduced by approximately 40.5% compared with MLI. The heat leakage of parallel VCS(P-VCS) was 76.6% lower than that of MLI. The minimum heat leakage of series VCS(S-VCS) was 83.79%, 72.75% and 37.36% lower than that of MLI, single VCS and P-VCS, respectively. Additionally, the heat leakage of the LH2 tank could be reduced to less than 10 W when LN2CS was installed. These results provide a design reference for the highly efficient storage of large LH2 tanks.

Design and optimization of a type-C tank for liquid hydrogen marine transport

As one of the most promising renewable energy sources, hydrogen has the excellent environmental benefit of producing zero emissions. A key technical challenge in using hydrogen across sectors is placed on its storage technology. The storage temperature of liquid hydrogen (20 K, or −253 °C) is close to absolute zero so the storage materials and the insulation layers are subjected to extremely stringent requirements against the cryogenic behaviour of the medium. In this context, this research proposed to design a large liquid hydrogen type-C tank with AISI (American Iron and Steel Institution) type 316 L stainless steel as the metal barrier, using Vapor-Cooled Shield (VCS) and Rigid Polyurethane Foams (RPF) as the insulation layer. A parametric study on the design of the insulation layer was carried out by establishing a thermodynamic model. The effects of VCS location on heat ingress to the liquid hydrogen transport tank and insulation temperature distribution were investigated, and the optimal location of the VCS in the insulation was identified. Research outcomes finally suggest two optimal design schemes: (1) when the thickness of the insulation layer is determined, Self-evaporation Vapor-Cooled Shield (SVCS) and Forced-evaporation Vapor-Cooled Shield (FVCS) can reduce heat transfer by 47.84% and 85.86% respectively; (2) when the liquid hydrogen evaporation capacity is determined, SVCS and FVCS can reduce the thickness of the insulation layer by 50% and 67.93% respectively.

Mechanical characteristics analysis and control algorithm for floating raft system with mass variation

The ship floating raft system adopts the integrated design of large liquid tanks and rafts, which can optimize the arrangement in the cabin and increase the intermediate mass of the system to achieve efficient vibration isolation of equipment. One of the major challenges is that the change of liquid mass in the tank will cause displacement of the raft, which will change the modal characteristics of the system and affect the stability of the vibration isolation system performance. This paper establishes a mechanical analysis model of a floating raft system under time-varying liquid mass conditions. Taking a ship variable mass floating raft system as the research object, the effect of mass change on the characteristics of raft displacement, isolator load distribution, and modal frequency of the vibration isolation system is analyzed. The analysis shows that when the liquid tank goes from full load to no-load state, its mass change accounts for 40% of the total mass of the raft, which will cause a large displacement of the raft and change the low order modal frequency of the system, bringing the risk of equipment safety and vibration isolation performance degradation. Therefore, an adaptive variable load control method is proposed to realize the raft attitude balance and load equalization optimization under the variable mass condition of the floating raft air spring system. The test results show that the proposed control method can automatically adapt to the large mass gradual change from full load to no load of the liquid tank on the raft, and control the displacement of the raft structure from about 10 mm to 1.5 mm, which effectively ensures the stability of the air spring system performance.

Sensitivity analysis of SPH parameters for long-distance water wave propagation

The hydrodynamics field continues to be interested in one of the classic free surface flow problems, the propagation of water waves. In this paper, long-distance water wave propagation is investigated using smoothed particle hydrodynamics (SPH). One of the mesh-free, Lagrangian particle approaches is SPH. The study’s goal is to derive a set of parameters appropriate for water wave propagation in a large wave tank. A 24.6 m wave gauge was placed in front of the piston wavemaker, which was used to replicate regular waves. Several SPH parameters are subjected to the sensitive analysis. In this investigation, DualSPHysics version 5.0, an open-source SPH solver, was employed. The findings demonstrated that a parameter with a substantial impact on the accuracy of wave profile is double-precision, particle distance, and coefficient of artificial viscosity.

A compact accelerator driven neutron source at the Applied Nuclear Physics Laboratory, Lund University

The Applied Nuclear Physics Group at Lund University has constructed a CANS (Compact Accelerator-driven Neutron Source). The CANS is based around a 3 MV, single-ended, Pelletron accelerator, which is used to impinge a 2.8 MeV deuterium beam into a beryllium target. The anticipated neutron production will be on the order of 1010 n/s in 4π sr, with future upgrades expected to increase neutron production to 1011 n/s. Neutron energy will be up to 9 MeV with peak emission at ∼5 MeV. Shielding and moderation will be provided by a large water tank surrounding the target, with exit ports to allow moderated neutrons to be directed to experiments. The thermal-neutron flux at the exit of the extraction ports is anticipated to be up to 106 n/cm2/s. The CANS will be used to forward the activities of the group in the area of neutron-activation analysis, in addition to a broader range of neutron related applications.

Numerical simulation of damping effect of ballast water system on motion response of immersed tunnel element

The OpenFOAM was extended to analyze the roll motion of an immersed tunnel element excited by outside waves and inside ballast water sloshing. The reliability of our numerical model was validated by comparing the results with related experimental tests. Then, the effect of filling depths of ballast water on damping roll motion of a 2-D tunnel cross-section excited by regular waves was analyzed, and the effect of tank width with constant filling weight on rigid-fluid coupling was also discussed. Results revealed that a crucial filling depth for best damping performance on roll motion of liquid-carrying structures exists between the dry condition and the filling depth corresponding to the most severe resonance condition. For the application of the tunnel element in this study, a dimensionless filling depth of 0.1 shows the best damping effect. Furthermore, for different tank widths with a constant filling weight, the damping effect of the ballast water is mainly dominated by the natural frequency of ballast water and has a negative correlation with the natural frequency, for small natural frequency of large tank width, the phase lag between roll motion and sloshing moment gets closer to the maximum damping lag of π/2 due to violent sloshing flow.

Modelling of fast fueling of pressurized hydrogen tanks for maritime applications

This paper studies fast fueling of gaseous hydrogen into large hydrogen (H2) tanks suitable for maritime applications. Three modeling methods have been developed and evaluated: (1) Two-dimensional computational fluid dynamic (CFD) modeling, (2) One-dimensional wall discretized modeling, and (3) Zero-dimensional modeling. A detailed 2D CFD simulation of a small H2-tank was performed and validated with data from literature and then used to simulate a large H2-tank. Results from the 2D-model show non-uniform temperature distribution inside the large tank, but not in the small H2-tank. The 1D-model can predict the mean temperature in small H2-tanks, but not the inhomogeneous temperature field in large H2-tanks. The 0D-model is suitable as a screening tool to obtain rough estimates. Results from the modeling of the large H2-tank show that the heat transfer to the wall during fast filling is inhibited by heat conduction in the wall which leads to an unacceptably high mean hydrogen temperature.

Analysis of the Hydrodynamic Characteristics in a Rectangular Clarifier under Earthquake-Induced Sloshing

Wastewater treatment plants, which play a crucial role in protecting the hydrosphere, are earthquake-prone infrastructures with large tanks and sensitive equipment. Damage to the structures in such facilities during seismic activity on the lithosphere can cause environmental pollution and threaten public health. Since the units/tanks in the treatment plants are not of different geometries and sizes, they may exceed the freeboard of the wave height due to the sloshing event. In this study, the sloshing dynamics of a rectangular type of clarifier were investigated. First, numerical parameters, boundaries, and initial conditions were validated using the results of an experimental campaign. Secondly, model conditions were kept constant, and geometry was enlarged (i.e., scaled-up) to investigate the variation of hydrodynamic forces near vulnerable equipment (such as scrapers and weirs) in clarifier. The numerical model was run for characteristics of two different earthquakes (i.e., Chi Chi-1999 and Kocaeli-1999). The results showed that dynamic pressure values near vulnerable equipment increased up to 120 times higher than the operating conditions. The maximum sloshing wave heights were calculated as 1.2 m and 1.45 m for Chi Chi (1999) and Kocaeli (1999) earthquakes, respectively.

A risk‐targeted seismic performance assessment of elephant‐foot buckling in walls of unanchored steel storage tanks

AbstractUnanchored steel storage tanks are used in industrial plants to store oil and other petrochemical liquids. In a major earthquake, such tanks may sustain different types of damage, including elasto‐plastic buckling in the shape of an elephant's foot, which is the object of the research. The methodology introduced in this paper consists of cloud‐based 1D site response analysis (SRA) and pushover‐based seismic performance assessment of the tank wall using a 3D non‐linear model of the tank. The SRA, which considers the recorded ground motions on the rock outcrop and the sample of interval shear‐wave velocity profiles, is carried out to estimate spectral accelerations at the tank impulsive period. By adopting the code‐based model of hydrodynamic pressures, the seismic demand on the tank wall is then calculated by pushover analysis. The risk‐targeted decision model is used for safety verification. The proposed methodology is demonstrated through an example of a large liquid storage tank for which it is shown that the fragility function for peak ground acceleration at the rock outcrop is on the left side of the target fragility function, indicating that the tank cannot be considered safe from elephant‐foot buckling. The introduced assessment process is relatively simple if the cloud‐based SRA is automated. However, further experimental and numerical investigations are required to confirm the validity range of the pushover analysis for the seismic performance assessment of tanks.

The effect of vaccine‐associated cross‐stitch vertebrae pathology on growth of farmed Atlantic salmon

AbstractA field study comparing two vaccine regimes against pancreas disease (PD) was carried out in 2018 S0 year class smolts at two commercial sea cage sites in southern Norway. The fish from the same hatchery source were immunized using licensed vaccines; either a DNA PD vaccine and a hexavalent oil‐adjuvanted vaccine (group A), or a heptavalent oil‐adjuvanted PD vaccine (group B). The experimental design included the two fish groups reared together (15% as group A and 85% as group B) in four large hatchery tanks. These fish groups were later transferred to four production cages at two separate sea sites (two cages per site). In the absence of any notable PD prior to the pre‐harvest sampling, the primary objective and outcome variables entailed evaluation of vaccine side effects and their impact on growth. The results show that vaccine and sea cage site significantly impacted prevalence and severity of a newly described pathology named cross‐stitch vertebrae. Further, moderate to severe cross‐stitch pathology (scores ≥3) resulted in significantly reduced growth.

Testing the Greenhouse Emission Model (GEM) for Pesticides Applied via Drip Irrigation to Stone Wool Mats Growing Sweet Pepper in a Recirculation System

Pesticide emissions to surface water from greenhouses with crops grown on substrates in open or closed systems may be significant. It is important, therefore, to test models such as the Greenhouse Emission Model (GEM), which was developed to assess these emissions as part of the Dutch authorization procedure for use of plant protection products in greenhouses. GEM was tested using an experiment in which imidacloprid and pymetrozine were applied via drip irrigation to stone wool mats growing sweet pepper. The irrigation system in such greenhouses consists of a mixing tank to prepare the nutrient solution and a series of tanks to treat and recirculate the drain water back to the mixing tank. Emissions may occur because (part of) this recirculation water may be discharged or leached to the surface water. GEM assumes that all tanks are perfectly mixed. GEM further assumes that the water in these mats is perfectly mixed and that the pesticide behavior can be simulated by assuming one perfectly mixed reservoir. The model predicted breakthrough of both pesticides out of the mats earlier than measured, and the measured maximum concentrations were approximately two times lower than predicted. We considered a series of possible causes, including a smaller water volume in the mats, a higher plant uptake factor, and sorption to the stone wool. The model performance improved by representing the mats as a sequence of two equally large tanks with plant uptake restricted to the first tank. We recommend to study the solute transport process and the distribution of plant roots in the mats in more detail to further underpin the hypothesis used and improve the model. After this first validation, the GEM model might also be used in other countries to forecast emissions of PPPs to surface water.