Tank Area Research Articles

Air and Seawater Quality Assessment Around Selected Area in Panjang Port Lampung Region

The port area is a diverse business district, both industry and other activities. Even though it is positioned far from residential areas, the impact of its activities indirectly still reaches the surrounding community. The environmental conditions of the port area need to be controlled routinely so that their management does not violate applicable regulations. Environmental management is needed so that risks arising from all activities can be controlled. Panjang Port as one of the well-developed fuel storage terminals as part of the Pelindo II region. This study has been designed to assess air quality and seawater quality around Panjang Port, Bandar Lampung, Indonesia. Several air quality parameters and marine water quality parameters were monitored from 2011 to 2013. The air quality sampling conducted in the fuel storage tank area and chemicals as well as supporting facilities. The air quality parameters are SO2, NO2, O3, CO, H2S, and dust. The results of data analysis showed several air quality parameters such as SO2, NO2, O3, dust, H2S, and NH3 are below the threshold of minimum quality standard. Only the CO parameter tends to increase semester to semester. The seawater quality parameters include physical, chemical, and biological quality. Almost the physical quality parameters are below the quality standard, thus the chemical quality too, except the pH and TSS tends to higher than a quality standard. In general, these studies on air quality and seawater quality at the Panjang Port have been carried out well and the results show that the environmental conditions for the Panjang Port area are still quite good, only it is recommended to add a green area around the site.

Post relocation of industrial sites for decades: Ascertain sources and human risk assessment of soil polycyclic aromatic hydrocarbons.

As a persistent organic pollutant, polycyclic aromatic hydrocarbons (PAHs) may still residually pollute industrial sites after relocation. This study investigated the contamination status of PAHs in the topsoils of three industrial legacy sites (the Shougang industrial ruins, the original Beijing coking plant area, and an abandoned gas station) that relocated more than 10 years ago from downtown Beijing. The sources of PAHs in the soil were qualitatively and quantitatively analyzed, and health risks were evaluated for different groups of people. The total concentration of 16 PAHs in the study area ranged from 371.1ngg-1 to 4073.9ngg-1. The pollution levels of the three study areas were abandoned gas station>Beijing coking plant>Shougang ruins. In terms of composition, low-ring aromatics accounted for the majority of the detected PAHs, and in the dry season, low-ring aromatics accounted for a higher proportion in the three areas than in the wet season. The comparison of the PAH diagnostic ratio and PMF model verification showed that the sources of PAHs in the Shougang ruins and the Beijing coking plant area were mainly those of biomass and coal combustion, accounting for 66.3% and 56.1% of the total detected PAHs, respectively; the PAH sources of the abandoned gas station storage tank area were largely that of petrol (33.9%) and diesel combustion (23.8%). Since these industrial sites were located in urban centers, this study also conducted a health risk assessment of the topsoil. The total carcinogenic risk range of the three contaminated sites was 1.41E-06 to 2.47E-05. Abandoned industrial sites have potential carcinogenic risks to human health. The government needs to conduct comprehensive risk assessments and remedial measures on soils of industrial legacy sites to achieve land reuse.

Investigation of the Superposition Effect of Oil Vapor Leakage and Diffusion from External Floating-Roof Tanks Using CFD Numerical Simulations and Wind-Tunnel Experiments

Based on computational fluid dynamics (CFD) and Realizable k-ε turbulence model, we established a numerical simulation method for wind and vapor-concentration fields of various external floating-roof tanks (EFRTs) (single, two, and four) and verified its feasibility using wind-tunnel experiments. Subsequently, we analysed superposition effects of wind speed and concentration fields for different types of EFRTs. The results show that high concentrations of vapor are found near the rim gap of the floating deck and above the floating deck surface. At different ambient wind speeds, interference between tanks is different. When the ambient wind speed is greater than 2 m/s, vapor concentration in leeward area of the rear tank is greater than that between two tanks, which makes it easy to reach explosion limit. It is suggested that more monitoring should be conducted near the bottom area of the rear tank and upper area on the left of the floating deck. Superposition in a downwind direction from the EFRTs becomes more obvious with an increase in the number of EFRTs; vapor superposition occurs behind two leeward tanks after leakage from four large EFRTs. Considering safety, environmental protection, and personnel health, appropriate measures should be taken at these positions for timely monitoring, and control.

Laterally Loading Experimental Study of Bearing Capacity Characteristics of Large-Diameter Bored Cast-in situ Deep and Long Pile

Base on the laterally static load and pile stress testing results of three kinds of different construction technology piles (post-grouting pile, expanded branches and bells by 3-way extruding arms, squeezed branch piles) in Tangshan LNG tank area, the distribution law of pile top deformation, moment and shear was analyzed under laterally load. The test results showed that: The H–Y0 curves of three different construction technology piles have no significantly the inflection point and have same deformation law; H–△Y0/△H curve show three stage: elastic stage, elastic–plastic stage and failure stage. The critical load value and ultimate load value of three different construction technology piles is same; The distribution rule of three piles’ moment increases firstly and then decreases with the pile depth, the support plate (fork) that is set the lower pile position has little effect of the top pile load and the bending moment; The relationship of foundation soil horizontal resistance force’s ratio coefficient (m) versus laterally load and pile top displacement are nonlinear, the curve of m and mud surface displacement (Y0) is fitted by exponential equation and m value corresponding to pile top displacement is gained, the design basis is provided for engineering design.

Dynamic Response Analysis of Large Arch-Roof Oil Tank Subjected to the Coupling Impact of Two-Source Blast Waves Based on Finite Element Method

Research on failure law of target oil storage tank subjected to the coupling impact of multiple blast waves is one of the theoretical bases for domino effect accident prevention and control of chemical industrial parks. Taking the coupling impact of two-source blast waves as an example, the propagation law of blast waves in air and the distribution law of peak overpressure on the surface of tank wall are analyzed, and the dynamic response laws of displacement, stress, strain and energy for a 5000 m3 atmospheric steel arch-roof oil tank are studied by using ANSYS/LS-DYNA. The results are compared with those subjected to single blast wave and show that the maximum overpressure peak value is formed near the ground in 0° direction on the surface of tank wall, which is 79.6% larger than that subjected to single blast wave. The peak values of displacement, stress and strain for the tank wall subjected to the coupling impact of two-source blast waves are 114.9%, 39.6%, 134.9% larger than those subjected to single blast wave, respectively. The failure mode of arch-roof tank subjected to two-source blast waves is to form multiple concave plastic deformation zones on the explosion face, which extend to the surrounding area and produce plastic hinge lines and form irreversible residual deformation and cracking finally. The analysis results can provide reference for explosion-resistant design of tank structure and reasonable layout of tank area scene.

Propagation probability of domino effect based on analysis of accident chain in storage tank area

Most of the hazardous materials in chemical storage tanks are flammable and explosive. Once a tank leaks, it would cause a fire or explosion, and subsequent domino accidents, forming catastrophic accident chain. In the present study, 165 domino accidents of storage tank area during 1970 and 2017 were analyzed to establish theoretic models and event tree. Probability distribution of initial accident and four typical accident node escalation models are picked up: fire → fire, fire → explosion, explosion → fire, explosion → explosion. Propagation probability model of accident chain was constructed, which consists of initial accident probability, accident node escalation probability and target tank failure probability. The efficacy and out-performance of the developed model have been demonstrated via a real-life simple case study.

Simulation of pressure tank leakage based on PHAST

Chemical plants usually store hazardous chemicals in high-pressure or low-pressure storage tanks in the form of pressurization, liquefaction, and low temperature. The poisonous gas in the tank is easily diffused. If a leakage accident occurs, it will cause personal injury and environmental pollution. In this paper, based on the propane acrylonitrile project in an industrial park, Major hazard identifications were identified for the tank area (risk level is Level 1), then PHAST software was used to simulate the leakage and diffusion of acrylonitrile storage tanks. It was concluded that the greater the wind speed, the leakage pore and the more stable atmosphere, the greater the leakage and diffusion of hazardous areas. And timely and intuitive prediction of the diffusion process and scope of toxic gases provide a scientific reference for taking corresponding countermeasures and on-site control after the accident.

Seasonal Variations of Heavy Metal Concentrations in Lake Water

Water Basin or tanks are very necessary attribute of either towns or rural environment. While urban lakes are present all over the world, in a country like India, the lakes in rural areas fulfill a variety of functions; drinking, irrigation, live-stock rearing and ground water recharge. In India, several water tanks recently have been astray, because of various manmade movements and the many of remain water tanks are degraded day by day. Many areas of water tanks in the world getting polluted by dumping and discharge of various kinds of effluents, wastes, etc., without any proper treatments., all these leads to degrading the quality of water and leads to changes in environmental conditions. For satisfactions of various water demands in local area, it is necessary to construct rainwater harvesting pits and to make channelizing of water to restore. So that, such water tanks serves many functions in a useful ways i.e. water may use for irrigation, to satisfy domestic demand and also may increase the ground water table and control of floods, etc. (Ganesan M 2008 et al, Mahapatra DM 2011 et al., Sudha M C 2013 et al.,). In this present study attempt has been made during Pre-Monsoon (April to May) and Post-Monsoon (September to October) periods to find the concentration levels of heavy metals, Arsenic (Ar), Copper (Cu), Cadmium (Cd), Chromium (Cr), Lead (Pb), Mercury (Hg), Zinc (Zn) and Boron (B). Sampling has been done by considering the inflow and the other outlet discharges, where the possibility of contaminations may enter into the water body by awning all over of the lake for taking samples, and also discussed the suitability of water for various demands, and suggested required management techniques to make water free from the contamination.

Modeling re-oxygenation performance of fine-bubble–diffusing aeration system in aquaculture ponds

Fine-bubble-diffusing (FBD) aeration system is widely used in aquaculture ponds. To maximize its re-oxygenation capability, it is needed to have a quantitative understanding of the reoxygenation performance. In practice, two indexes, namely oxygen volume mass transfer coefficient (KLa) and standard oxygen transfer efficiency (E), are commonly used to measure the re-oxygenation performance. However, few mathematical models are available to accurately predict these two indexes. The objective of this regard was to develop such a model driven by commonly available data. In this regard, the results from 54 group laboratory tests were regressed on four independent variables, including air flow rate (Qg), aeration tube length (L), submerged water depth of the diffuser (hd), and plane-view tank area (Acs). The regression revealed that both KLa and E are negatively related to hd and Acs, but they are positively related to L. In addition, KLa was found to be positively related to Qg, whereas E was found to be negatively related to Qg. Two regression models, one for KLa while another for E, are expected to be effective tools for operating FBD aeration system in practice to maximize its re-oxygenation capability though they may need to be further verified using field data.

Analysis of Domino Effect Based on Bayesian Probability Explosion and Oil Tank Fire in Mixing Tank Area

Based on the domino effect and Bayesian network, this paper establishes the accident probability model of hybrid storage tank area. Taking a chemical storage tank area as an example to analyze the accident domino effect caused by accident parameters such as thermal radiation and explosion shock wave, we analyzed and calculated the damage probability of shock wave over-pressure and pool fire to adjacent equipment in liquefied gas storage tanks by considered that the occurrence of a pool fire accident in a single tank is a result of the incident. The results show that the control measures are combined with the energy transfer sequence of the accident, so that the safety protection measures proposed under this scenario can more effectively ensure the safety of the chemical tank farm.

A new method to calculate sedimentation velocity of particle group with three-plane ECT based on the best correlation function

ABSTRACT A novel method to calculate the flow velocity of solid in a solid–liquid two-phase system is induced in this paper by electrical capacitance tomography (ECT). Taking the slime settlement as an example, the concentration change of three planes in the settling tank is measured using ECT. Moreover, the settling velocity of continuous frames in different sensor planes employing the best correlation function is calculated. The results show that slime has a higher and more uniform settlement velocity in the center area of the settlement tank. A 0.02–0.04 cm/s deviation is found between the calculated velocity of clarifying interfacial layer when slime passing through the ECT sensor and the experimental data. Remarkably, the time point is in good agreement with the experimental result which is between 7 and 13 s, indicating that the method can be used to estimate the settling velocity of solid in a two-phase flow.

Dynamics and Control of Liquid Level in Annular Conical Tank Process: Modelling and Experimental Validation

Objectives: The present work has been carried out to prove the superiority of IMC based PID control strategy over the conventional PID, based on simulation studies and experimental validation on an annular conical tank liquid level nonlinear process. Methods/Statistical Analysis: First principles based Mathematical Model of an annular conical tank liquid level nonlinear process has been developed based on the mass balances and outlet flow hydraulic characteristics. Linearization of the nonlinear model at a specific steady-state operating point led to the theoretical development of state-space and standard first order transfer function models. Open loop and closed loop experimental studies on a computer controlled physical setup were performed to identify the parameters of a FOPDT Model with variable gain and time constant. IMC based PID controller was designed and compared to the conventional PID controller. Findings: The variation in process parameters was attributed to two factors: (a) the variation in annular cross sectional area of the conical tank at different levels, and (b) the variation in outlet flow resistance. The IMC based PID controller has been shown to exhibit superior performance in terms of quantitative performance indices such as ISE, IAE, ITAE, rise time, settling time and percentage overshoot, at four different steady-states. Application/Improvements: Study of Modelling of annular conical tank process and a systematic methodology of process system identification from experimental setup have been reported. The advantages of IMC based PID controller design over the conventional PID tuning method has been experimentally verified. Keywords: Annular Flow Conical tank process, FOPDT model, System Identification, PID controller tuning, IMC based PID.

Measurement of the connectivity of runoff source areas on a bare soil surface in a laboratory experiment

As soil erosion has been severely constraining agricultural production and economic sustainability in the Loess Plateau in central China, study of hydrologic connectivity of tilled slope surfaces based on higher accuracy has major implications for prevention of soil erosion. This study explores the properties of hydrologic connectivity of microtopographic slope surfaces (contour tilled, at gradients of 15°, 20°, and 25° in respective events) under artificial rainfall (at 90 mm h⁻¹) produced in laboratory experiments. A spatial metric, flowlength, was acquired and tested to quantify the connectivity of runoff source areas and was calculated as the average lengths of the runoff pathways. The grid cells, which measured lengths of flow paths (6 to 10 mm) in runoff source areas at different slopes, accounted for over 46% of the total grid cells on the raster-based map. Flow path lengths increased when the slope gradient was steeper and decreased when the surface roughness increased. The ratio of the surface area connected to the outlet to the total surface area of the soil tank (C, %), which equals the parameter C, or the ratio of the surface runoff area connected to the downstream outlet to the total surface area of the study area, peaked quickly and then became stable under accumulative rainfall. The steeper the slope, the shorter amount of time it took for C to reach its peak; the greater the average C, the better hydrologic connectivity. Flowlength could be an important index for characterizing the structural properties of the hydrologic connectivity of a slope surface, and also simplified hydrograph and relative surface connection function can be used to characterize the runoff generation process and the mechanism of the soil surface and the properties of its hydrologic connectivity. These results are instrumental in providing guidelines on and insight into the role of hydrologic connectivity at a microtopographic scale.

Risk Assessment on BTEX Exposure at Fuel Storage Tank Area in Gasoline Station

Risk Assessment on BTEX Exposure at Fuel Storage Tank Area in Gasoline Station

Water saving and productivity benefits of SRI: a study of tank, canal and groundwater irrigated settings in South India

Abstract Paddy, which is predominantly cultivated under the conventional inundation method, is the largest water consuming crop in India. Given looming water scarcity, the inundation method of paddy cultivation is no longer sustainable. A newly introduced method of paddy cultivation, popularly known as the System of Rice Intensification (SRI), is reportedly helping to reduce water consumption and increase land productivity. SRI has now been in practice for some years in India but the various impacts of SRI on water saving, land and water productivity as well as on profitability which are expected to vary in different ecological settings – namely in tank, canal and groundwater irrigated areas – remain largely unexplored. In this study, using data collected from a total sample of 300 farmers from three different settings in Tamil Nadu state, an attempt has been made to fill this gap. The study shows that by adopting the SRI method farmers can save about 40% of irrigation water and increase land productivity by about 46% while reducing the cost of cultivation by 23% over the conventional inundation method. While increasing irrigation water productivity and economic water productivity substantially, SRI also generates an additional profit of Rs 17,169/acre (1 USD = INR 70.12; 1 acre = 4047 m2) compared to that realised by non-SRI farmers.

Hydropower system operation stability considering the coupling effect of water potential energy in surge tank and power grid

This paper aims to study the hydropower system operation stability considering the coupling effect of water potential energy in surge tank and power grid. Firstly, the mathematical formulation for hydropower system with surge tank that connected to power grid is established. Then, the hydropower system operation stability is investigated. The coupling effect mechanism of surge tank and power grid on stability is revealed. Finally, the formula for critical stable sectional area (CSSA) of surge tank considering power grid is derived and analyzed. The results indicate that the free vibration equation for hydropower system with surge tank that connected to power grid under step load disturbance is a ninth order linear homogeneous differential equation. The domain at the bottom left corner of the critical line on the Proportional-Integral plane is the stable domain. The proposed novel analytic solution of stable domain has a high precision and is feasible for practical applications. The formula for CSSA of surge tank considering power grid realizes the unity of the coupling effect of water potential energy in surge tank and power grid. The CSSA contains four terms, i.e. headrace tunnel term, penstock term, governor term and power grid term.

Stability analysis of hydro-turbine governing system including surge tanks under interconnected operation during small load disturbance

Abstract The operating modes of hydro-turbines have a significant influence on the stability of hydropower plants. In this study, a linking method of multiple hydropower plants and the frequency equation of the interconnected system are proposed. The state space modeling of the hydro-turbine governing system (HTGS), including the pipe system and surge tanks, is established under interconnected operating modes. The proposed model is used to simulate the small fluctuation process under isolated and interconnected operations based on the parameters of two simulated hydropower plants. The stability of the systems under different operating conditions is compared, and the effect of surge tank area on the stable region is analyzed. The results indicate greater stability under interconnected operating conditions because of the change in regulating modes of the turbines. A hydropower plant with a smaller proportion of the total output has an insignificant effect on the system when the interconnected system is properly stable. In addition, the difference in the surge tank periods should be maintained outside the adverse range.

Unravelling long-term source removal effects and chlorinated methanes natural attenuation processes by C and Cl stable isotopic patterns at a complex field site

The effects of contaminant sources removal in 2005 (i.e. barrels, tank, pit and wastewater pipe sources) on carbon tetrachloride (CT) and chloroform (CF) concentration in groundwater were assessed at several areas of a fractured multi-contaminant aquifer (Òdena, Spain) over a long-term period (2010–2014). Changes in redox conditions, in these chlorinated methanes (CMs) concentration and in their carbon isotopic compositions (δ13C) were monitored in multilevel wells. δ13C values from these wells were compared to those obtained from sources (barrels, tank and pit before their removal, 2002–2005) and to commercial solvents values in literature. Additionally, CMs natural attenuation processes were identified by C-Cl isotope slopes (Λ).Analyses revealed the downstream migration of the pollutant focus and an efficient removal of DNAPLs in the pit source's influence area. However, the removal of the contaminated soil from former tank and wastewater pipe was incomplete as leaching from unsaturated zone was proved, evidencing these areas are still active sources. Nevertheless, significant CMs degradation was detected close to all sources and Λ values pointed to different reactions. For CT in the tank area, Λ value fitted with hydrogenolysis pathway although other possible reduction processes were also uncovered. Near the wastewater pipe area, CT thiolytic reduction combined with hydrogenolysis was derived. The highest CT degradation extent accounted for these areas was 72 ± 11% and 84 ± 6%, respectively. For CF, the Λ value in the pit source's area was consistent with oxidation and/or with transport of CF affected by alkaline hydrolysis from upstream interception trenches. In contrast, isotope data evidenced CF reduction in the tank and wastewater pipe influence areas, although the observed Λ slightly deviates from the reference values, likely due to the continuous leaching of CF degraded in the non-saturated zone by a mechanism different from reduction.

Saturation characteristics for stability of hydro-turbine governing system with surge tank

Abstract This paper aims to study the saturation characteristics for stability of hydro-turbine governing system with surge tank. Firstly, the mathematical model of hydro-turbine governing system under load disturbance is established, and the equivalent independent stability discriminants are presented. Then, the saturation characteristics for stability are analyzed. Using analytical stability discriminants and stable domain, the generation mechanism of saturation characteristics is revealed, and a distinguishing method of critical saturation state is proposed. Finally, the concept of saturation sectional area of surge tank is proposed. The distribution and partition for stability states is illustrated, and a combined tuning method of sectional area of surge tank and governor parameter is proposed. The results indicate that, for hydro-turbine governing system with surge tank, the fourth-order discriminant boundary is always the critical boundary of stable domain. The second-order and third-order discriminant boundaries determine the stable domain under saturation state. The equality for fourth-order discriminant has two real solutions when the system is saturated. The saturation sectional area of surge tank is the sectional area that makes the system reach critical saturation state. Domain C of the distribution and partition figure for stability states is the most favorable domain for the system stability.

Prenursery of the Pacific white shrimp in a biofloc system using different artificial substrates

This study evaluated different artificial substrates during pre-nursery of Pacific white shrimp in a biofloc system. Post-larvae (PL 5–80 PL L−1) were raised in 60 L tanks filled with 52 L of chlorinated seawater (35‰) and 6 L of the microalga Chaetoceros muelleri. Four treatments were performed, including control (no artificial substrate), Bidim® (geotextile), mosquito net screen (2 mm mesh) and Needlona® (polyester fiber). The total surface area of artificial substrate comprised 100% of the tank area (0.89 m2). PLs were fed nine times a day using commercial feed. Molasses was added in all treatments four times a day at an average carbon:nitrogen ratio of 14.7:1. The experiment was carried out until the PLs reached PL20, and during this time, water quality, survival, weight gain and survival to salinity stress were all evaluated. Water quality parameters remained within the accepted levels for shrimp rearing, with the exception of total suspended solids (TSS) in mosquito net screen and control, which had the highest values (507 ± 5.50 mg L−1 and 565 ± 23.46 mg L−1, respectively). Using Needlona® as artificial substrate increased the survival rate (91 ± 11.6%) and reduced TSS (42%) when compared to the control. No significant differences were observed in final weight and survival to salinity stress. Among the different substrates, Needlona® was the most suitable for application in Pacific white shrimp prenursery in the biofloc system, essentially because it could maintain levels of solids suspended in water without the use of clarifiers or water exchange, resulting in higher survival.