Tanker Loading Research Articles

Polycyclic aromatic hydrocarbons in Niger Delta soil: contamination sources and profiles

The distribution and sources of PAHs in soil as well as PAHs profiles have been investigated in areas with anthropogenic pollution in the Niger Delta (Nigeria) such as Warri and Ughelli. PAHs were identified in 21 soil samples (0–10cm upper layer) collected in May, 2003. The typical total PAHs level in Niger Delta soil ranged from 182 ± 112 - to - 433 ±256 íg/kg dw. PAH concentrations in soil samples from Warri Refinery, Tanker Loading point and Ugboko via Rapele oil field were quite high ( the mean ÓPAH concentrations were 433, 402 and 384 íg/kg dry weight respectively). The dominant PAHs in soil samples were pyrene, naphthalene and benzo[k]fluoranthene. The soil total PAHs (PAHtot.) concentration, normalized to organic carbon content (OC), ranged from 11.4 to 47.2 mg PAHtot. /kg OC; and showed that organic matter of the soil samples from Quality Control Centre, Ugelli West is highly contaminated with PAHs and had a value of 47.2 ± 31.2 mg PAHtot./kg OC. Two and three ring aromatic hydrocarbons predominated in soil samples from Ughelli West, Tanker Loading point and Delta Steel Company, which is indicative of petrogenic origin.

Sloshing Loads in Liquid-Storage Tanks with Insufficient Freeboard

Seismic ground motions excite long-period sloshing response in liquid-storage tanks. A minimum freeboard is needed to prevent the sloshing waves from impacting the roof of tanks. Since freeboard results in unused storage capacity, many tanks are not provided with the sufficient freeboard. As a result, sloshing waves impact the roof, generating additional forces on the roof and tank wall. This article presents a simple method of estimating these forces.

Experimental investigation of pressure distribution on a rectangular tank due to the liquid sloshing

Pressure variations and 3D effects on liquid sloshing loads in tanks have been carried out experimentally. Recently, considerable advances have been made in the development of numerical techniques for studying the liquid sloshing on large structures. However, there is a lack of high quality experimental data that may be used for validating the analytical and numerical solutions obtained. This paper describes the results of the research project conducted at the Hydroulics Laboratory of Civil Engineering Faculty of Istanbul Technical University. The primary objective of the project is to investigate the pressure distributions at different locations and 3D effects on liquid sloshing. In this purpose, an experimental setup is designed to study the non-linear behavior and damping characteristics of liquid sloshing in partially filled 3D rectangular tank. Both several configurations of baffled and unbaffled tanks are studied.

A Low-Voltage 4.6 GHz Injection Locked Frequency Divider in Standard 1.8 V 0.18 µm Complementary-Metal–Oxide–Silicon Technology

A fully integrated 1.5 V, 4.6 GHz injection-locked frequency divider is designed and implemented for low-voltage 5 GHz wireless local area network front-end circuit applications. An LC tank load is used in the oscillator design to decrease power consumption. The measurement results show a resonant frequency range from 4.4 to 4.6 GHz for the control voltage Vc varying from 0 to 1.5 V. The chip has an additional capacitor to provide steady power and to decrease the power noise injected into the output resonant signal. This injection locked frequency divider is implemented using the TSMC 0.18 µm single-poly-six-metal 1.8 V silicide process. The entire chip area is 2.1×1.2 mm2.

Thermal and economical analysis of a central solar heating system with underground seasonal storage in Turkey

Thermal performance and economic feasibility of two types of central solar heating system with seasonal storage under four climatically different Turkey locations are investigated. The effects of storage volume and collector area on the thermal performance and cost are studied for three load sizes. The simulation model of the system consisting of flat plate solar collectors, a heat pump, under ground storage tank and heating load based on a finite element analysis and finite element code ANSYS™ is chosen as a convenient tool. In this study, the lowest solar fraction value for Trabzon (41°N) and the highest solar fraction value for Adana (37°N) are obtained. Based on the economic analysis, the payback period of system is found to be about 25–35 years for Turkey.

Optimal planning of cargo operations at bunkering tankers with respect to dynamical character of their parameter restrictions

The present paper is devoted to the problem of bunkering tankers' optimal cargo planing. The brief analysis of existing approaches for solving the multiple-criterion optimisation problem is fulfilled with respect to specific features of the bunkering control processes. The complex three-component non-linear criteria taking into account restrictions at both cargo tanks capacity and tanker's loading conditions is developed. The solution of the non-linear mathematical programming problem for the model of the tanker in the form of rectangular pontoon is presented and confirms efficiency of the suggested criterion. The necessity of dynamical character of restrictions applying is proved for the problem. The fuzzy system for the restrictions issuing is also developed.

Calculating Benzene Concentration Emitted During Tanker Loading

Benzene emissions occur during marine vessel loading operations. These emissions are regulated in several countries. Accordingly, we developed a one-dimensional benzene diffusion model advancing in the vertical direction within cargo tanks. Unlike other models, the model presented in this paper is based on a 1/10 scale modeling of eddy diffusion at the liquid surface during initial loading operations and advection under the tank roof during final loading operations. The model input parameters include loading rate, flow rate, cargo tank size, and temperature dependent saturated concentrations. The validity of the model is demonstrated by comparisons with onboard measurements. Other models exist. However, they are based on empirical estimates rather than rational modeling.

SPRAYER BOOM DYNAMIC EFFECTS ON APPLICATION UNIFORMITY

Boom acceleration and height effects on spray deposit were determined for distinctly different track conditions,droplet spectra, and sprayer tank loads using an instrumented self-propelled sprayer with a 27 m boom at 12.8 km/h. Trackconfigurations were: smooth, a 20 cm high bump, and a 20 cm high bump and an opposing 20 cm deep dip. Droplet spectraincluded 255 and 588 .m volume median diameters (Dv0.5) as determined by laser diffraction. Sprayer tank loads were eitherhalf capacity or empty. Results indicated three-dimension accelerations ranging from 1.8 to -1.1 g, 14.3 to -6.7 g, and 20.7to -11.0 g and boom end height effects ranging from 2.0 to 1.2 m, 2.6 to 0.5 m, and 3.5 to 0.4 m for smooth, bump, and bumpand dip tracks, respectively. Small droplets of 255 .m (Dv0.5) resulted in a spray coverage range (with maximum coefficientof variation, CV) from 11% to 22% (55%). Small droplets produced Pearson correlation coefficients between coverage andlocalized, instantaneous boom height ranging from -0.40 to -0.58. Large droplets of 588 .m (Dv0.5) resulted in a spraycoverage range (with maximum CV) from 9% to 18% (39%). Large droplet Pearson correlation coefficients between coverageand localized, instantaneous boom height ranged from 0.49 to -0.62. Spray coverage significantly (P

A Low-Voltage Complementary-Metal–Oxide–Silicon 4.4-GHz Voltage Control Oscillator Design

A fully integrated 1 V, 4.4 GHz Inductor–Capacitor (LC) voltage control oscillator is designed for low-voltage high-frequency circuits and used in 5 GHz wireless LAN front-end system applications. An LC tank load is used in the oscillator design to decrease the power consumption. The measurement results show a tuning range from 3.903 GHz to 4.42 GHz for Vtf varying from 0 V to 1 V. The phase noise is -95 dB/Hz at 100 KHz. The bias voltage inside the chip has an additional capacitor to provide steady power and decrease the power noise injected into the output resonant signal. This oscillator is implemented using the TSMC 0.35 µm one-poly-four-metal 3.3 V logic process. The total chip area is 1.235×0.902 mm2.

Respiratory Health in Aseptic Packaging with Hydrogen Peroxide: A Report of Two Cases

In the consumer market, there is an increasing demand for various types of fruit juices. To prevent rapid deterioration of the juice the packaging is performed aseptically, commonly employing 5–35% hydrogen peroxide. The workers who operate the packaging machines may encounter inhalation exposure to hydrogen peroxide vapours, and incidental splashes or skin contact with the substance are also possible. Hydrogen peroxide (H 2 O 2 ) is an endogenous metabolite of oxygen and occurs at submicromolar concentrations in aerobic cells. Hydrogen peroxide is able to penetrate biological membranes like water, and the substance oxidises biomolecules unless it is degraded to oxygen and water which readily happens in the presence of catalase or glutathione peroxidase. After oral ingestion or surgical application to body cavities, the rapid breakdown of H 2 O 2 may result in oxygen embolism, sometimes with serious consequences. In local contact, hydrogen peroxide is irritating or corrosive depending on the concentration. Workers engaged in tank loading complained of nose irritation at a measured vapour concentration of 3.5 mg/m . In a controlled study with volunteer subjects, the threshold concentration of the airborne vapour for airway irritancy was 10 mg/m . In the eye, 5% hydrogen peroxide water solution is irritating, and a concentration of 8% or higher caused irreversible damage in the rabbit eye . In rabbit skin, a 10% solution in water was mildly irritating and a 35% solution caused epidermal necrosis probably due to oxygen embolism in the capillaries, whereas 50% or higher concentrations were corrosive. Many workers have noted that inadvertent skin contact to the more concentrated solutions causes white spots which spontaneously disappear within some hours; the change of colour is due to formation of oxygen microbubbles in the skin. Based on a review of historical skin testing results involving hairdressers at two dermatological clinics, hydrogen peroxide is not a skin sensitiser. Long term effects of hydrogen peroxide vapours in the respiratory system have not been adequately elucidated. A limited study performed fifty years ago with dogs suggested that hydrogen peroxide induced lung toxicity at 10 mg/m . In the open literature, there is a case report of a heavily exposed dairy worker who developed interstitial pneumonitis, which the authors attributed to hydrogen peroxide exposure. Presently, the lack of reliable data precludes any possibility of making a health risk assessment for workers who are typically exposed to hydrogen peroxide via inhalation. It would therefore be worthwhile to gather such information from occupational health monitoring programmes and, after critical data analysis, to report them. The present paper deals with the symptoms and respiratory morbidity experienced by a small group of workers exposed to hydrogen peroxide at a fruit juice factory. Althought this investigation is limited by the small number of persons involved, and the restricted method employed, the special circumstances of a change in exposure from high to reasonably low levels, and monitoring of the health status over time, add more weight to the study.

Analysis of tuning in resonant inverter

A model and analysis are presented for tuning of a resonant inverter. The model uses linearised phase-frequency characteristic of a tank load near the resonant frequency. To demonstrate the validation of the model, a low-power prototype was implemented using a CD4046 phase-locked loop chip in the tuning circuit.

ZCS High Frequency Inverter for Induction Heating with Duplicated Tuned Load Circuit

We have reported a ZCS high frequency inverter for induction heating uses elsewhere. Its load circuit is composed of a parallel tuned tank load circuit having a heating coil with relatively small inductance, leading to limited applications for the inverter. This paper presents a duplicated tuned load circuit to deal with a tank load having a heating coil with a higher inductance, to widen application range of the inverter. It is found that the high frequency inverter having the improved tank load circuit reveals a high efficiency reaching 89 percent. Its circuit operation and performance are analyzed on the basis of computer-aided simulation and its actual behaviors are examined from a practical point of view for a feasible breadboard.

A Novel Approach for Oil and Gas Separation by Using Gas Hydrate Technology

Abstract: It is known that gas hydrates remove the light ends from reservoir fluids. Therefore, controlled hydrate formation in reservoir fluids could be an attractive option for separating oil and gas; that is, to replace conventional production facilities. In this communication we present the results of an integrated experimental and modelling study on the feasibility of the process, and the impact of the various parameters on the rate of hydrate formation. The study investigated the impact of parameters, such as mixing, water history, temperature, pressure, volume of reactor, heat removal requirements, and the quality of separated liquid. The work identified the major parameters and some of the technological requirements. Based on the experimental data, a simplified mass transfer model was constructed to simulate the kinetics of the separation process and to calculate the reactor volume and heat requirements at a specified degree of conversion. The results showed that it is possible to remove most of the lights from the liquid hydrocarbon phase by hydrate formation. The resulting liquid phase could be suitable for pipeline export or tanker loading after some treatment. Associated gas could be recovered locally from the hydrate phase. Alternatively, in cases where there is no infrastructure for transporting this gas, it might be exported as a hydrate slurry, as proposed by Gudmundsson and coworkers.

Comparison of tanker drivers' occupational exposures before and after the installation of a vapour recovery system

The purpose of this study was to compare tanker drivers' occupational exposure level before and after the installation of vapour recovery facilities at 14 service stations. Road tanker drivers are exposed when handling volatile petrol liquid in bulk in the distribution chain. The drivers' exposure was studied during the unloading operation as the bulk petrol flowed into underground storage tanks, displacing vapours in the tank space and causing emission to the environment and the drivers' work area. The exposures were measured again when the dual point Stage I vapour recovery systems were installed for recycling vapours. Short-term measurements were carried out in the drivers' breathing zones by drawing polluted air through a charcoal tube during unloading. The samples were analysed in the laboratory by gas chromatography for C3-C11 aliphatic hydrocarbons, tert-butyl methyl ether (MTBE), tert-amyl methyl ether (MTAE), benzene, toluene and xylene. The road tanker loads delivered consisted of oxygenated and reformulated petrol (E95 and E98 brands), which contained on average 13% oxygenates. Before the installation of the vapour recovery system, the geometric mean (GM) concentration of aliphatic hydrocarbons was 65 mg m-3 (range 6-645 mg m-3) in the drivers' breathing zones. After the installation at the same service stations, the corresponding exposure level was 8.3 mg m-3 (range < 1-79 mg m-3). The GM of the MTBE concentrations was 8.6 mg m-3 (range 1-67 mg m-3) without vapour recovery and 1.5 mg m-3 (range < 0.1-10 mg m-3) with vapour recovery. The differences between the aliphatic hydrocarbons and the MTBE exposure levels during the unloading of the road tankers without and with vapour recovery were statistically significant (p < 0.05).

Investigation of a combined solar-heat pump system for residential heating. Part 2: simulation results

In this study, a mathematical model of a solar-assisted heat pump system with latent heat energy storage for residential heating in Turkey was developed. The model consists of dynamic and heat transfer relations concerning the fundamental equipment in the system such as solar collector, latent thermal energy storage tank, compressor, condenser, evaporator and building heating load. Some model parameters of the system were calculated by using experimental results. It was found that the model agreed well with the experimental results. Copyright © 1999 John Wiley & Sons, Ltd.

Computer simulation of a two phase thermosyphon solar domestic hot water heating system

The present work deals with a theoretical analysis by computer simulation of a two phase thermosyphon solar domestic hot water system using R-11 as a working fluid. The performance was studied by the aid of a simulation procedure for a typical day period divided into equal time intervals of 15 min. Instantaneous values of solar radiation intensity and ambient temperature were applied at the beginning of each time step. The insolation was calculated according to the procedure suggested by ASHRAE. The variation of ambient temperature during the day was approximated by a sine function. The variation of working fluid properties with temperature was also taken into account. The computer program and calculation procedure were first validated by comparing the results with established results of single phase systems. Then, calculations were performed for the two phase thermosyphon system to evaluate mass flow rate, saturation pressure and temperature in the collector and condenser, together with tank temperature, and collector and condenser thermal efficiencies. These calculated values were obtained for three cases, namely, the no loading case of no water withdrawal from the tank, continuous loading and intermittent loading. The results obtained showed that, in the two phase system, the saturation pressure and temperature increase continuously during the day and follow the tank temperature pattern. This makes the system pressure dependent on the tank loading. The collector efficiency did not reveal a serious change with the loading condition. This behavior differs from that which occurs in the single phase system, where the collector efficiency increases considerably with loading. Comparison of the two phase system with a single phase system of the same collector area and tank volume showed a significant increase in collector efficiency and tank temperature for the case of the two phase system.

Distribution of Selected Trace Metals and Its Relation with Environmental Pollution

Middle East crude oils, tar balls, and marine and fresh waters were analyzed, and V, Ni, Mg, Fe, Cu, and Zn were determined. Marine water samples have V, Ni, Mg, Cu, and Fe at 1900, 1600, 1.2, 110, and 112 times the natural levels, respectively. On the other hand, freshwater samples have V, Ni, Mg, and Fe at 10, 11, 2, and 13.7 times the natural levels, respectively. There is no Zn pollution in either the marine or fresh water, while the Nile River has no Cu pollution. Crude oils have contents 1.3, 1.1, and 5 times the natural levels for V, Ni, and Fe, respectively. Tar balls have Mg and Cu at 15 and 2 times the natural levels. Generally, V/Ni, V/Mg, and (V/Ni + Mg) indices calculated for marine and fresh waters have identical values (<1), while higher values were obtained for tar and crude oils. These data, especially for water samples, may reflect a progressive contamination of oil during tanker loading operations, fuel oils, and waste discharge in the studied area. Also these data may serve as a guide for detecting anomalies to human-made pollution.

Exposure of tanker drivers to gasoline and some of its components.

The purpose of this study was to measure the exposure of road tanker drivers at work to gasoline and some of its components. The occupational hygiene measurements were made in two depots (one in northern Finland and the other in southern Finland) and in 11 service stations of a Finnish oil company during the loading and delivery of road tankers. Of the 21 measurements made, four were taken during top submerged loading of the road tankers and six during bottom loading at the depot. Eleven measurements were made during delivery at service stations. The duration of measurements varied from 10 to 44 min. The exposure of road tanker drivers to C3-C11 hydrocarbons of gasoline was under 300 mg m-3 during bottom loading measurements and during top loading exceeded 300 mg m-3 two measurements (50%). During delivery at service stations the exposure to C3-C11 hydrocarbons of gasoline exceeded 300 mg m-3 in four measurement (36%). The exposure of road tanker drivers during delivery depended mainly on the distance between working area and the emission point of discharging vapours from the tank, vents and wind direction. The mean exposures of road tanker drivers to benzene during loading and delivery were 1.1-18 mg m-3 in various situations. The mean exposures to n-hexane, to toluene and to xylene were 0.7-6.0, 1.4-11 and 0.8-4 mg m-3, respectively. The exposures to methyl-tert-butyl ether were between 13 and 91 mg m-3. All measurements were made during the summer. However, the temperature varied between 4 and 22 degrees C.

Sublethal biological effects and chemical contaminant monitoring of Sullom Voe (Shetland) using mussels (Mytilus edulis)

SynopsisMussels (Mytilus edulis), collected from up to nine sites, were used to monitor the degree of chemical contamination (by petroleum hydrocarbons and organotins) and the associated sublethal biological effects (scope for growth) in the vicinity of the North Sea oil terminal at Sullom Voe from 1982 to 1989. Gluss Voe represented a ‘clean reference’ site at which mussels showed a very low level of contamination and a consistently high ‘scope for growth’ (&gt;20 J g−1 h−1). Spatial and temporal changes in the concentration of polyaromatic hydrocarbons in the mussel tissues reflected the major sources of oil inputs and the number and size of oil spillages around the tanker loading jetties. Hydrocarbon concentrations in mussels at the oil tanker jetties were typically 10-fold higher than mussels at Gluss Voe. The concentrations of tributyltin in the tissues were greatest in the area near the tanker jetties and showed a steady decline between 1986 and 1989 which correlated with a decline in tanker activity (r = +0.98).The results demonstrated a significant correlation between the net quantity of oil spilled during the month prior to sampling and the accumulated aromatic hydrocarbons in the mussel tissues (r = +0.89). In addition, there was a significant negative relationship between scope for growth and the log concentration of aromatic hydrocarbons in the mussel tissues (r = −0.83). Toxicological interpretation of tissue residue data indicated that the decline in SFG was caused by accumulated PAHs rather than TBT. Although mussels showed a significant reduction in scope for growth in Sullom Voe they were still able to grow, reproduce and maintain their populations. When these results are placed in a wider geographical context and compared with other UK sites, it is apparent that the ‘clean reference’ site in the Shetland has the lowest recorded levels of organic contaminants, and that other sites in the vicinity of the Sullom Voe Oil Terminal are less contaminated and impacted than many estuaries on the UK mainland.

CONSEQUENCES OF THE BEHAVIOUR OF ACTIVATED SLUDGE PLANTS WITH COMBINED SEWAGE INFLOWS

The paper deals with the dynamic behaviour of activated sludge plants resulting from combined sewage inflows. Implications for the planning and operation of activated sludge plants are inferred from this behaviour. On the basis of a measured rain event dynamic simulation is used as a tool to investigate the influences of combined sewage inflows. Following an increase in the water inflow rate due to rain, a significant increase in concentration of nitrogen is observable at the outflow of the activated sludge tank The reason for this is the total Kjeldahl nitrogen influent load peak generated by the combined sewage inflow, together with displacement of biomass to the secondary sedimentation tank. Since the effluent concentration peaks are caused by inflow load peaks, measures must be taken to buffer these load peaks in the inflow zone. Best results can be achieved with inflow storage. Given a sufficiently large storage tank and optimum load management, a relatively low ammonium effluent value could be maintained even at high inflow rates. Optimum inflow control is feasible if both the water volume and the nitrogen concentration can be measured at the inflow and can be influenced by means of storage tanks. Dynamic simulation continues to be useful during operation, and can support tank control.