Aboveground Tanks Research Articles

A modular approach for the design of the Alicia3 climbing robot for industrial inspection

The system proposed in this paper is the Alicia3 robot, which is based on the Alicia II module. Its aim is to inspect non‐porous vertical walls like those of aboveground petrochemical tanks, with a wide range of surface materials and cleanliness levels. To meet this aim, pneumatic‐like adhesion has been selected for the system. The system is also required to move over the surface at a suitable speed, to pass over obstacles and to have a suitable payload to carry mission‐specific instrumentation. The robot design mainly aimed at finding a solution with a high degree of modularity, so that it can easily be disassembled for maintenance purposes and to replace consumable parts such as the wheels and the sealing, making its design easier. Some onboard control algorithms have also been introduced to increase system reliability and reduce energy consumption.

Large Wave Tank Dispersant Effectiveness Testing in Cold Water

ABSTRACT Research experiments were completed to determine the viability of using chemical dispersants on two crude oils in very cold water conditions. Tests were completed at Ohmsett (the National Oil Spill Response Test Facility in Leonardo, New Jersey) in late February and early March of 2002. Ohmsett is a large outdoor, above-ground concrete tank (203 m long by 20 m wide by 3.4 m deep) filled with 9.84 million gallons of salt water. The tank has a wave-generating paddle, a wave-dissipating beach, and mobile bridges that transport equipment over its surface. A refrigeration unit was installed to ensure that the water was kept at near freezing temperatures during the entire test program. A total of twelve large-scale tests were completed. Corexit 9500 and Corexit 9527 were applied to fresh and weathered Hibernia and Alaska North Slope crude oils, on cold water (-0.5 to 2.4 °C), at dispersant-to-oil ratios (DORs) ranging from 1:14 to 1:81. The average wave amplitude for the tests ranged between 16.5 and 22.5 cm and the average wave period was between 1.7 and 1.9 seconds. The effectiveness of the dispersant in each test was documented through extensive video records and by measurement of the residual oil remaining within the containment boom at the end of each test. The results clearly show that both dispersants were effective in dispersing the two crude oils tested in cold-water conditions.

Influence of the roof on the natural periods of empty steel tanks

The influence of a fixed roof on the natural periods of vibrations of thin-walled aboveground steel tanks with clamped boundary conditions at the base is studied. Tanks with open-top, self-supported roofs, and roofs supported by rafters are considered, along with different tank aspect ratios. The self-supported roof geometries considered include dome, cone, shallow cone, and flat roofs; whereas the rafters supported roofs geometries study cone, shallow cone, and flat roofs. The effect of the aspect ratio, along with the roof configuration on the natural periods is discussed. It was found that the vibration of empty tanks with a fixed roof is dictated either by cylinder modes or roof modes of vibrations. For self-supported roofs predominant roof modes resulted, whereas for tanks with roofs supported by rafters, cylinder modes dominate the dynamic behavior of the tank. Roof dominant modes had natural periods that remain constant regardless of the aspect ratio considered. Cylinder modes, on the other hand, were characterized by natural periods that showed a linear dependence with the aspect ratio of the tank.

Using mathematical models to estimate exposure to workplace air contaminants

Air sampling is traditionally used to assess exposure to airborne contaminants. However, failing to account for exposure variability by taking only a few measurements, and failing to record information on exposure determinants for the time periods monitored, substantially limit the conclusions one can draw from the data. Mathematical modeling offers a partial solution to this problem, and is a useful adjunct to exposure monitoring. The modeling approach is illustrated with two examples; the model predictions agree with limited air monitoring data. The first example is estimating short-term benzene exposure levels (specifically, 15-min time weighted averages, TWAs) among delivery truck drivers while offloading gasoline to small above-ground tanks. The benzene mass emission rate from the tank headspace is assumed to be constant and a function of the benzene content of the gasoline, temperature, and tank fill rate. Vapor is emitted from the fill hole into a surrounding near field zone which contains the driver’s breathing zone; airflow into the near field depends on the local random air speed. Monte Carlo simulation is used to examine variability in 15-min TWA exposure; a substantial proportion are predicted to exceed the 15-min TWA benzene exposure limit of 5 ppm. The second example is estimating ethylene oxide (ETO) gas levels in a well-mixed room due to use of a desktop medical sterilizer device. The variable ETO mass emission rate was modeled based on information provided in the product literature, and was used to derive a general equation for the room ETO concentration given a set of room volume and dilution ventilation values. For a poorly ventilated room, the model predicted that, the average concentration during the sterilization phase could exceed the 8-hr TWA ETO exposure limit of 1 ppm, and that during the sterilization and aeration phases the 15-min TWA ETO limit of 5 ppm could be exceeded.

Environmental Regulation and Substitution Between Sources of Pollution: An Empirical Analysis of Florida’s Storage Tanks

Stringent and very specific environmental regulations may spur behavioral responses by the regulated entities that can offset the intended pollution control goals. I empirically examine the effects of regulating underground storage tanks for petroleum products and hazardous substances, focusing on their possible substitution or complementarity with a less stringently regulated alternative, aboveground tanks. Longitudinal county-level tank data from Florida reveal that the relationship between underground and aboveground tanks changed, from one of complementarity to one of substitution, after the regulations were issued. Tank installations are affected by resident characteristics that enter in the firm’s calculus of the damages from leaks.

Free vibration analysis of aboveground LNG-storage tanks by the finite element method

Recently, in proportion to the increase of earthquake occurrence-frequency and its strength in the countries within the circum-pan Pacific earthquake belt, a concept of earthquake-proof design for huge structures containing liquid has been growing up. This study deals with the refinement of classical numerical approaches for the free vibration analysis of separated structure and liquid motions. According to the liquid-structure interaction, LNG-storage tanks exhibit two distinguished eigenmodes, the sloshing mode and the bulging mode. For the sloshing-more analysis, we refine the classical rigid-tank model by reflecting the container flexibility. While, for the bulging-mode analysis, we refine the classical uncoupled structural vibration system by taking the liquid free-surface fluctuation into consideration. We first construct the refined dynamic models for both problems, and present the refined numerical procedures. Furthermore, in order for the efficient treatment of large-scale matrices, we employ the Lanczos iteration scheme and the frontal-solver for our test FEM program. With the developed program we carry out numerical experiments illustrating the theoretical results.

World Current Trends of LNG Storage Tanks And Latest Technology of Aboveground Tanks

World Current Trends of LNG Storage Tanks And Latest Technology of Aboveground Tanks

Unearthing Fannie Bay Gaol: Archives and the Archaeology of Water Management in Darwin's First Purpose-built Prison

In 1998 the author conducted an archaeological excavation at Fannie Bay Gaol, Darwin (Northern Territory, Australia). This focused on features that related to early water management; specifically one of two wells dug in 1883 and one of two subterranean water tanks constructed in 1884. With the aid of early plans and other historical references the location of the well and water tank were determined with what was considered to be a reasonable degree of accuracy. Excavation found no evidence for a well. Instead a shallow pit was uncovered, possibly relating to a later above-ground water tank. The subterranean tank was successfully located and partially excavated. This revealed that the tank was probably the first of the two to be built in the Gaol, and was possibly infilled as recently as the mid-twentieth century.

Biogeochemical assessment of natural attenuation of JP-4-contaminated ground water in the presence of fluorinated surfactants

The biogeochemistry of the natural attenuation of petroleum-contaminated ground water was investigated in a field study. The focus of the study was a fire training site located on Tyndall Air Force Base in Florida. The site has been used by the Air Force for approximately 11 years in fire fighting exercises. An on-site above-ground tank of JP-4 provided fuel for setting controlled fires for the exercises. Various amounts of water and aqueous film forming foams (AFFF) were applied to extinguish the fires. The sources of contamination included leaks from pipelines transporting the fuel, leaks from an oil/water separator and runoff and percolation from the fire fighting activities. Previous investigations had identified jet fuel contamination at the site, however, no active remediation efforts have been conducted to date. The goal of this study was to use biogeochemical monitoring data to delineate redox zones within the site and to identify evidence of natural attenuation of JP-4 contamination. In addition to identifying several hydrocarbon metabolites, fluorinated surfactants (AFFF) were detected down-gradient of the hydrocarbon plume.

Design Method of Steel Liner-Anchor System on Interior Wall of PC Vessel.

A design method was proposed for the steel liner-anchor system on an interior wall of a prestressed concrete vessel of a LNG above-ground tank. The stress analyses were performed on the liner-anchor system to determine the forces on the liner and displacements of the anchor under concrete imposed strain. The model for the analysis consists of a series of springs that represents ideal flat liners, bent plates and anchors. An allowable value was given for the anchor displacement and the required diameter of the stud was derived to prevent fracture of the stud anchor. Elastoplastic analyses were performed on the liner plates under prescribed displacement to calculate the surface strain of the liner plates. The allowable value was determined for the liner surface strain and the lower limit value of the anchor spacing was determined to avoid rupture of the liner.

Hatchery production of Florida red tilapia seed in brackishwater tanks under natural-mouthbrooding and clutch-removal methods

Hatchery production of Florida red tilapia seed (eggs, sacfry and fry) in brackishwater (12 ppt) tanks was studied on Lee Stocking Island (Exuma Cays, Bahamas) under two methods of broodstock management. Six above-ground tanks (34.2 m 2) were each stocked with 240 year-class 1 breeders (avg. wt. = 143 g) at a ratio of 3 females to 1 male. Seed production was monitored either under the natural-mouthbrooding method by collecting free-swimming (i.e., post-yolksac stage) fry from tanks every 8–16 days, or under the clutch-removal method by removing free-swimming fry from tanks, and eggs and sacfry from the mouths of brooding females every 15–16 days, and assessing the numbers of each. Seed production over a 3-month period under the natural-mouthbrooding method (3.3 seed m −2 day −1) was significantly lower ( P < 0.001) than that obtained under the clutch-removal method (91.7 seed m −2 day −1) which is among the highest reported for tilapia hatcheries. Poor seed production under the natural-mouthbrooding method was attributable to cannibalism of eggs and fry by adults. Hatching success of eggs in upwelling incubators averaged 64.8% with effects of densities of 462, 923, 1385 and 1846/1 not differing significantly ( P > 0.05). Fry obtained from artificial incubation were significantly ( P < 0.05) larger (9.9 mg vs. 7.5 mg) and more viable than those obtained through natural mouthbrooding as evidenced by higher survival (73.9% vs. 49.7%) during a 29-day sex-reversal period. The results suggest that the clutch-removal method, while more labor intensive, yields markedly higher numbers of viable fry for growout.

Hatchery production of Florida red tilapia seed in brackishwater tanks: the influence of broodstock age

Abstract. Production of Florida red tilapia seed (eggs, sacfry and fry) in 34-m2 above-ground tanks using recirculated brackishwater (12 ppt) was studied over a 5-month period on Lee Stocking Island (Exuma Cays, Bahamas). Four tanks were stocked with year class 1 (YCI) breeders, while 2 tanks were stocked with year class 2 (YCII) breeders at densities of 200 and 240/tank (5·9 and 7·1/m2), respectively, and at a sex ratio of 3 females to 1 male, beginning in November 1988. Seed production was measured by removing free-swimming fry from tanks and eggs and sacfry from the mouths of brooding females, and assessing the number of each at 15 to 16-day intervals from February to June 1989. Average seed production (seed/m2/day) was significantly higher in YCI (52·3) than in YCII (36·0) broodstock, indicating the advantages of replacing broodstock with yearling breeders each year.

Operational Experiences with LNG Storage Tanks

British Gas has 20 above-ground LNG tanks in service, representing some 250 tank-years of experience. No major incidents have occurred with any of these tanks. Operational problems have been experienced with tanks, bunds, LNG valves and pumps; these have all been overcome without recourse to warming up or decommissioning the tanks. This paper summarizes British Gas's operational experiences, describing, in particular, how problems have been overcome. One above-ground tank has been decommissioned recently, for operational rather than technical reasons. This provided an excellent opportunity for detailed study of the condition of an LNG tank after 14 years of operational service. In addition mention is made of the (now decommissioned) in-ground LNG storage tanks, formerly used by British Gas.

Mobay may begin water treatment venture

Mobay unveiled late last month a new wastewater treatment system at its Baytown, Tex., chemical complex that may well become the basis for a new business for the U.S. arm of the West German chemical giant, Bayer A.G. Although it is as yet undecided, according to a company spokesman, the new system developed by Bayer in West Germany will either be licensed or the company will go into the business of selling the hardware for the system. The process, called Bayer Tower Biology, is an above-ground biological aeration system that breaks down organics via aerobic digestion much faster than aeration ponds. Since the water is treated in above-ground tanks, the risk of groundwater contamination is reduced, the company says. In the process, wastewater from the company's Baytown complex flows through a primary clarification tower where lighter-than-water contaminants rise to the top and are taken off by mechanical skimmers. Heavier-than-water solids sink to the bottom and ...

CONSTRUCTION OF PRESTRESSED CONCRETE DIKES FOR LNG ABOVEG-ROUND TANKS

CONSTRUCTION OF PRESTRESSED CONCRETE DIKES FOR LNG ABOVEG-ROUND TANKS

IDENTIFICATION AND INITIAL RECOVERY OF JET A FUEL FROM THE GROUND UNDERLYING A TANK FARM AT PALM BEACH INTERNATIONAL AIRPORT

ABSTRACT A recent surface fuel spill incident by tank overflow at a 220,000 gal above-ground airport tank farm led to a single monitoring well installed at the request of the state. This well disclosed previously spilled Jet A fuel at the water table, 5 ft below grade. Eight monitoring wells averaging 7 ft deep were completed in 3 days, revealing a surprisingly confined pool of fuel in fine sand estimated at 24,000 ft2 but with over 30 in. of fuel in some wells. Monitoring wells 40 ft away showed a complete absence of fuel. Leaking from underground piping was tested and eliminated as a possible source. Above-ground spills, it was concluded, were insufficient as a source. Inventory records failed to show any losses. Gas chromatic analysis of the product confirmed that it was Jet A, and therefore not JP-4 from an abandoned Air Force fuel main. The source of fuel was concluded as primarily from the practice of daily fuel tank sumping to the ground, which ceased in 1974. Significantly, the spill was 10 years old and had not moved. Initial recovery was by slotted drum, later replaced by a 70 ft by 3 ft trench to the water table, gravel backfilled. Recovery of product only, without water pumping, was by an electrical chemical metering pump, continuously, at the rate of product flow to the trench, averaging 23 gal per day. Investigations of groundwater quality in nearby monitoring wells by the state agency failed to show any hydrocarbons, analyzed down to 5 parts per billion. The closest water well, 1,800 ft away, showed no contamination. Bench scale testing demonstrated that monitoring well fuel thickness overstates fuel thickness in the ground, and that trenches concentrate fuel thicknesses like monitoring wells. Tight cost control was maintained, with monitoring wells costing under $50 each, a recovery trench under $2,000, and recovery pumping under $1,000. By-product recovery revenue has offset some recovery costs.

Sludge formation in storage of diesel oil with additive

1. During prolonged storage of DS-11 oil with 5% TsIATIM-339 additive, sludge accumulates on the tank bottoms; this sludge is an emulsion of water and oil, stabilized by the surface-active components of TsIATIM-339, including the stable free radicals present in the additive. 2. The emulsion sludges consist of 90–99% oil, 1.4–5.5% solid component, and 0.8–8.6% water. The solid component consists of 75–83% ash elements, including 31–54% barium. The number of paramagnetic particles per gram of solid component of the sludge may vary from 3 · 1017 to 6 · 1018. 3. Oil losses during long-term storage due to sludge formation may amount to 0.03–0.08% in aboveground tanks and 0.18–0.19% in trench tanks, which exceeds the established standard by a factor of 5–10.

Cryogenic In-Ground Storage

Proctor, R.C., Comstock-Pritchard Liquefaction Corp., Kansas City, Mo. Introduction Demand for gases storable as liquids at low temperature and pressure was relatively small in the past, and the storage of these gases as liquids was accomplished in above-ground double-wall insulated tanks. Recently there have been several large installations of above-ground single-wall insulated tanks erected for the storage of propane, butane and anhydrous ammonia. Refrigerated storage of LPG and anhydrous ammonia is not considered cryogenic storage because these gases are liquefied at atmospheric pressure at temperatures substantially higher than those associated with cryogenic work. When industries, like the natural gas industry, begin to think of storage in volumes of a billion cu ft of gas stored as a liquid, such as Transco's installation, and then multiples of this volume, the project then justifies an intensive study and evaluation of all possible methods of storage. This design is the result of years of research and study following the disastrous fire resulting from the rupture of the Cleveland above-ground tanks. Certain lessons and subsequently fire tests after Cleveland pointed to the following:1. LNG must he contained where it cannot run into occupied areas.2. The intensity of an LNG fire is not as severe as those of gasoline or propane.3. The intensity of fires from LNG or propane increases rapidly as the material is allowed to spill out on warm ground, which increases the vaporization rate. It is evident that any refrigerated storage should be contained in the minimum surface area. This means dikes must he as high as possible with minimum surface exposure, the ultimate being in-ground.4. Spillage or overflow from tanks must be contained. This is a serious problem on above-ground tanks, and just a diked area is not an adequate solution. On the Arzew project, the initial above-ground ship-loading tanks are connected to overflow into the in-ground storage. The cryogenic in-ground storage tank offers a solution to these problems. Its level is maintained below ground where it cannot run out over the surface. Rather than a large diked area for rapid vaporization in case of an accident, only the top of the hole could be exposed. The ground containing the LNG is frozen to −260F storage temperature with an ice ring over 30 ft thick making a vast cold pool. Any variation boiloff as a result of a fire would be a small per cent of what could be expected above ground. The concept of prefreezing a ring of frozen earth and then excavating within this frozen ring a cryogenic in-ground storage unit, developed by Conch International Methane Ltd., was demonstrated for the first time in Oct., 1961, at Lake Charles, La. This has been one of the outstanding developments from the standpoint of both investment and safety. On the Transco job, double-walled above-ground tanks together with their foundations and dikes were evaluated with in-ground prestressed concrete tanks and cryogenic in-ground storage. This evaluation showed savings, by using cryogenic in-ground storage, of approximately $1 million when compared to above-ground storage, and $500,000 when compared to in-ground prestressed concrete tanks. Cryogenic in-ground storage is no panacea for storage of LNG, but the geology at the Transco site and the properties of the frozen earth at this location were particularly favorable to this type of storage. This paper presents the design and construction features of the storage unit for the Transcontinental Gas Pipeline Co. that is now under construction in the New Jersey Meadows near Carlstadt, N. J. JPT P. 393ˆ