Crude Oil Storage Tanks Research Articles

Effect of alloy element on corrosion behavior of the huge crude oil storage tank steel in seawater

Corrosion behaviors of the high strength low alloy (HSLA) steel and the carbon steel for a huge crude oil storage tank in seawater were studied by electrochemical methods and microanalysis techniques. The research found the alloy element had decreased corrosion rates for a long time but slightly increased corrosion rate at the beginning of experiments. Potentiodynamic tests results showed that all specimens exhibited active corrosion behavior, and corrosion rate tended to increase as a result of adding alloying elements. However, the loss weight results showed the corrosion rates of the HSLA steel were much smaller than those of carbon steel. Furthermore, more alloying elements led to a remarkable decrease in the corrosion rate. The reasons for these by electrochemical impedance spectroscopy (EIS) showed that the corrosion process of all samples showed two stages. At the first 144h, EIS of all samples showed one increasing capacitance arc. The carbon steel showed the least corrosion rate, which was due to that the corrosion rates depended on the active site on the sample surface and the alloy effects were minor. After 144h of immersion, EIS of the HSLA steels showed two capacitance arcs and the EIS of the carbon steel always showed one capacitance arc, which indicated the HSLA steel can form a compact corrosion scale. The HSLA steel showed the smaller corrosion rate than carbon steel, which was due to that the corrosion rates depended on the protective ability of corrosion scales and the alloy elements were help to form a compact corrosion scale on sample surface. The EDS results indicated that Cr, Mo and Al were distributed densely at the interface between the rust layer and the steel surface which helped to improve corrosion resistance for the HSLA steel. Corrosion of the HSLA steels was suppressed by insoluble compound formed near the surface.

Characterization of emulsified water in petroleum sludge

Increasing depletion of conventional oil resources has driven interest in recovery of oil resources from petroleum sludge. To improve the quality of recovered oil, it is essential to maximize the removal of emulsified water, dissolved salts, and other impurities. Therefore, this study was conducted to characterize the emulsified water droplets and salt in petroleum sludge through differential scanning calorimetry (DSC). To accomplish this, samples of three different types were evaluated before and after centrifugation. The results indicated that with DSC water content and eutectic of salt hydrates could be identified during controlled heating from −60°C to room temperature. Moreover, a new equation to retrieve water droplets size distribution according to the cooling phase of the DSC thermogram from 50°C to −60°C is proposed. Samples collected from a mixed petroleum sludge storage tank and a tank cleaning wastewater reservoir were found to contain emulsified water droplets with a broadened size distribution, and the freezing peaks shifted from −44°C to −20°C as the diameter of water droplets increased. Additionally, water droplets in the sample collected from the crude oil storage tank were very strongly emulsified and were relatively uniform, with a diameter of 2.7–3.3μm. Following centrifugation, small droplets were found in the upper oily layer, suggesting that de-emulsification pre-treatment prior to water/oil/solid phase separation is essential to obtain high-purity oil resources. This is the first time DSC is employed to characterize emulsified water and deduce water droplets size distribution in petroleum sludge. These results are essential and useful for optimization of petroleum sludge treatment.

Calculation of Wax Precipitation Magnitude in Crude Oil Storage Tanks in Khark Island

During the different seasons of the year, the temperature of the oil tank goes up or down. The present work is composed of two parts, evaluation of the crude oil temperature and determining amount of wax precipitation. The numerical method has been developed for solving the energy equation and a thermodynamic model has been developed to predict wax precipitation based on average crude oil temperature. In the experimental investigation, a crude oil storage tank in Khark Island is selected as the case study and average crude oil temperature have been measured for two days and compared by the numerical result.

Degradation of petroleum hydrocarbons from bottom sludge of crude oil storage tanks using in-vessel composting followed by oxidation with hydrogen peroxide and Fenton

In this research the feasibility of aerated in-vessel composting process followed by chemical oxidation with H2O2 and Fenton for removal of petroleum hydrocarbons from oily sludge of crude oil storage tanks was investigated. The ratios of the sludge to immature compost were 1:0 (as abiotic control), 1:2, 1:4, 1:6, 1:8 and 1:10 (as dry basis) at a C:N:P ratio of 100:5:1 and 55 % moisture content for a period of 10 weeks. Six concentrations of H2O2 and Fenton were added to the compost mixture for a period of 24- and 48-h reaction times. Results showed that petroleum hydrocarbons removal in ratios of 1:2, 1:4, 1:6, 1:8 and 1:10 were 66.6, 73.2, 74.8, 80.2 and 79.9 %, respectively. The results of the abiotic experiments indicated that the main mechanism of hydrocarbon removal in the composting reactors was biological. The application of combined composting and chemical oxidation demonstrated a remarkable (about 88 %) overall removal. The study showed that in-vessel composting combined with chemical oxidation is a viable choice for the remediation of the sludge.

Biodegradation of petroleum hydrocarbons of bottom sludge from crude oil storage tanks by in-vessel composting

The feasibility of aerated in-vessel composting of sludge waste from crude oil storage tanks for total petroleum hydrocarbons (TPH) removal was investigated. Immature compost as an amendment for supplementing nutrients, organic matter and microbial activity was added to the sludge. The ratios of sludge to compost were 1 : 0 (as control), 1 : 2, 1 : 4, 1 : 6, and 1 : 8 (as dry basis) at a C : N : P ratio of 100 : 5 : 1 and 55% moisture content for a period of 10 weeks. TPH removal was 67%, 73%, 75%, and 80%, respectively. The results of the control reactors indicated that the main mechanism of TPH removal in the composting reactors was biological. In-vessel composting by addition of immature compost as amendment is a viable choice for sludge remediation.

UNS N08810 합금의 입계부식손상과 원인 분석

Corrosion failure of petrochemical facilities is one of the difficulties in maintenance, since operating conditions of crude oil production, storage, and refinement are very aggressive. UNS N08810, which has been used for crude oil transportation pipes and storage tanks in petrochemical industries, shows good resistance to general corrosion and localized corrosion in several environments. Among its environments, UNS N08810 showed better corrosion resistance in fuel gas containing sulfuric acid and phosphoric acid and sulfur. However, ductility and toughness at high temperature over about <TEX>$500^{\circ}C$</TEX> were greatly reduced due to microstructural change. In general, welding process is the representative method to join the parts in industrial components. Because the alloy by welding can be sensitized and corroded, the manufacturing process should be controlled. In this work, UNS N08810 was used and heat treatment conditions including solution and stabilization treatments were controlled. Oxalic acid etch test by ASTM A262 Practice A was done to evaluate the qualitative sensitization in room temperature. Huey test by ASTM A262 Practice C was done to evaluate the intergranular corrosion rate in boiling 65% <TEX>$HNO_3$</TEX> solution. Also, the microstructure by thermal history was analyzed. Experimental alloy showed high intergranular corrosion rate and its corrosion mechanism was elucidated.

Imaging near‐surface defects using step‐frequency ground‐penetrating radar

Step‐Frequency GPR (SFGPR) investigations were carried out at the location of a crude oil storage tank at a petroleum refinery. The storage tank was founded on an elevated platform (tank‐pad). Subsidence of a portion of the tank‐pad led to cracking of its bottom steel plates and subsequent leakage of crude oil. SFGPR imaging was done within and outside the tank, in the frequency range of 10‐260 MHz, to understand the cause of the subsidence. Complex signal analysis was useful in identifying a series of cavities in the subsurface, in the depth range of 2–15 m, close to the location of subsidence of the tank‐pad. In order to stabilize the foundation of the tank, the subsurface area infested with cavities was grouted systematically. SFGPR imaging was done again after grouting, in the same area in the same manner to evaluate the efficacy of grouting and check for presence of remnant cavities. Results of the SFGPR investigations, before and after grouting, which aided restoration of the foundation of the oil tank, are discussed.

Removal of Oil Tank Bottom Sludge by Novel Biosurfactant, JE1058BS

Maintenance of crude oil storage tanks requires periodical washing of the tanks before ordinary repairs can be made to these systems. In this study, crude oil derived sludge in the oil storage tank was treated with various surfactants to disperse the sludge into a miscible fraction, including JE1058BS, a new biosurfactant produced by Gordonia sp. strain JE-1058. Phylogenetic analysis of the 16SrRNA sequence of the strain JE-1058 identified Gordonia polyisoprenivorans. The sludge was efficiently removed by dispersion with biosurfactant at concentrations of 1-10 g/L, with stable dispersion at 10 g/L for 3 weeks. Addition of the BS caused no significant changes except for water content in the physicochemical factors such as density, viscosity, and sulfur/nitrogen content, suggesting that the novel biosurfactant JE1058BS is useful for oil tank bottom sludge treatment.

Determining the Subsidence of Oil Storage Tank Walls from Geodetic Leveling

In this paper the monitoring for subsidence in crude oil storage tanks by the method of Geodetic leveling is discussed. The monitoring network consisted of three control points established about 100m from the tank and 16 studs established at the base of the tank. From the control points, the stud locations were leveled using a geodetic level with parallel plate micrometer and telescopic staves. All levels were run in forward and reverse directions and the measurements were carried out in 2003, 2004 and 2008. Adjustment of observation was carried out using the least squares estimation model to determine the elevation of each stud position in the three measurement epochs together with their accuracy standards. Comparisons were made of the calculated movements from the three measurement epochs and the associated accuracies calculated from the least squares model. Analysis of the results indicated that with the exception of one stud ( stud 8), all other studs emplaced had moved and the movements ranged from 0.91mm to 13.06mm

Determination of the Ovality of Crude Oil Storage Tanks Using Least Squares

In the processing of field measurements, the observations are adjusted using the least squares principle which gives unbiased estimate of the parameter sought together with their accuracies. In this paper, the use of the Least Squares model in the determination of the tank radius, centre point coordinates and ovality are discussed. The circular cross section of the crude oil storage tanks was divided into sixteen monitoring stations at equal intervals around the tank and at an elevation of 2m from the tank base. Total station instrument was then used to carry out angular and linear measurements by method of multiple intersection to reflectors held on the studs. The field measurements were post processed and adjustment of observation carried out by Least Squares adjustment method. The adjusted coordinates together with the computed radius were then used to determine tanks ovality. All data processing and adjustment were carried out with the aid of MATLAB Software for the 2003, 2004 and 2008 measurement epochs.The results of the study revealed an expansion of the tank shell between 2004 and 2008 measurement epoch. The radius of the tank was computed to be 38.187m in 2003 and 2004 and 38.205m in 2008 respectively.

Effects of the Exterior Surface Paint Color on Sludge Formation in a Crude Oil Storage Tank (Case Study: Khark Island)

One of the major problems associated with crude oil storage tanks is the settling of heavy particles and formation of accumulated sludge at the bottom of the tank. In this study, the temperature distribution within a crude oil storage tank has been calculated numerically and the effects of exterior surface paint color on the tank temperature have been investigated. A thermodynamic model has been developed on the basis of the equilibrium between the liquid and solid phases to calculate the solid-phase precipitation. Employing a sedimentation equilibrium model, the deposition of the solid phase and sludge formation has been evaluated. To validate the numerical results, Khark 28th crude oil storage tank is selected as a case study and the numerical values of sludge height and oil temperature have been compared to the experimental data, where good agreement is observed. Finally, the effects of the exterior surface paint color on sludge formation of a crude oil storage tank have been investigated. The results show that applying a darker color instead of the existing one may lead to 1.5 million USD/year savings for 40 crude oil storage tanks.

An overview on ADCO crude oil storage tanks

PurposeThe purpose of this paper is to present an overview of storage tank incidents and the causes of the incidents. The paper also seeks to present a brief overview on Abu Dhabi Company for Onshore Oil Operations (ADCO) experience of Jebel Dhanna (JD) export terminal.Design/methodology/approachMajor hazard installations (MHIs) store large quantities of flammable material in storage tanks. Storage tanks represent important capital assets and are often critical operational items. The failure of a tank can have several undesirable effects such as endangering personnel, affecting the environment and interrupting the operator's business. The storage tank incidents and ADCO's experience on operating of an export terminal are collected from several sources such as technical articles, text books, internet web sites, and internal reports. The incidents and the causes of the incidents are reviewed and summarised. The ADCO's experience in operation of a crude oil tank farm are outlined.FindingsThe world has witnessed 480 tank fire incidents in the period 1951‐2003. The major cause of storage tank fire incidents was due to lightning. The leaks and the spills from the tanks were due to corrosion, operation, improper or lack of maintenance, poor design and/or maintenance of piping systems, fire and explosion. Although several studies have been carried out to record the tank incidents and the causes of the incidents the studies were not comprehensive. Many tank fire incidents that occurred have not been recorded in the previous studies. ADCO have been operating the JD crude oil terminal for more than three decades without a major incident. This was achieved through the design, operation and maintaining of the tanks in accordance with international standards, periodical studies by expert consultancy, and regular development of the control and protection systems with up‐to‐date technology.Originality/valueThe findings highlight that an international storage tank incidents database should be established to compile the scattered data in one site. The tank incidents database encourges the MHIS to publish tank incidents. The database can assist MHIs as well as the research institutes to learn lessons from the incidents. MHIs publishing articles is one of the means of sharing and exchanging the experience with similar installations and institutes.

Methanobacterium petrolearium sp. nov. and Methanobacterium ferruginis sp. nov., mesophilic methanogens isolated from salty environments

Two methane-producing archaea, designated Mic5c12(T) and Mic6c05(T), were isolated from sludge deposited in a crude oil storage tank and a tubercle on the interior of a pipe transporting natural gas-containing brine, respectively. The isolates were Gram-staining-variable, non-motile rods and grew only on H(2)/CO(2). Strain Mic6c05(T) produced methane from some alcohols without showing any growth; strain Mic5c12(T) did not utilize alcohols. The optimum growth conditions for strain Mic5c12(T) were 35 °C, pH 6.5 and 0-0.68 M NaCl and for strain Mic6c05(T) were 40 °C, pH 6.0-7.5 and 0.34 M NaCl. Strain Mic5c12(T) was halotolerant and strain Mic6c05(T) was halophilic. Comparative 16S rRNA gene sequence analysis revealed that strains Mic5c12(T) and Mic6c05(T) belonged to the genus Methanobacterium and their closest relative was Methanobacterium subterraneum A8p(T) (97.3 and 97.9 % 16S rRNA gene sequence similarity, respectively). The findings from the 16S rRNA gene sequence analyses were supported by analysis of McrA, the alpha subunit of methyl-coenzyme M reductase. On the basis of phylogenetic analyses and phenotypic characteristics, two novel species are proposed, Methanobacterium petrolearium sp. nov. and Methanobacterium ferruginis sp. nov., with type strains Mic5c12(T) (=NBRC 105198(T) =DSM 22353(T)) and Mic6c05(T) (=NBRC 105197(T) =DSM 21974(T)), respectively.

Iron-Corroding Methanogen Isolated from a Crude-Oil Storage Tank

Microbiologically influenced corrosion of steel in anaerobic environments has been attributed to hydrogenotrophic microorganisms. A sludge sample collected from the bottom plate of a crude-oil storage tank was used to inoculate a medium containing iron (Fe(0)) granules, which was then incubated anaerobically at 37 degrees C under an N(2)-CO(2) atmosphere to enrich for microorganisms capable of using iron as the sole source of electrons. A methanogen, designated strain KA1, was isolated from the enrichment culture. An analysis of its 16S rRNA gene sequence revealed that strain KA1 is a Methanococcus maripaludis strain. Strain KA1 produced methane and oxidized iron much faster than did the type strain of M. maripaludis, strain JJ(T), which produced methane at a rate expected from the abiotic H(2) production rate from iron. Scanning electron micrographs of iron coupons that had been immersed in either a KA1 culture, a JJ(T) culture, or an aseptic medium showed that only coupons from the KA1 culture had corroded substantially, and these were covered with crystalline deposits that consisted mainly of FeCO(3).

Research on High Heat Input Welding of the High Strength Electro-Gas Flux-Cored Wire Used for Large Storage Tank

Baosteel cooperated with the China’s welding consumable company and developed an electro-gas welding wire BH610-EG, which is a flux-cored welding wire and can match the high strength steel B610E. In this paper, the electro-gas welding technological tests are carried out by B610E with the thickness of 21 mm and 40 mm and BH610-EG wire with the diameter of 1.6 mm. And values of the heat input of electro-gas welding experiments are in the range of 80~100kJ/cm. The main conclusions can be obtained as follows: (1) In condition of high heat input, the electro-gas welding process using BH610-EG wire is very stable, the weld surface is good. (2) Various mechanical properties of the welded joints can meet the design requirements of the storage tanks. (3) The new developed electro-gas flux-cored welding wire BH610-EG can match with B610E steel and meet the requirement of high heat input of the crude oil storage tank.

Ability of indigenous Bacillus licheniformis and Bacillus subtilis in microbial enhanced oil recovery

Microbially produced lipopeptide have been isolated and studied for microbial enhanced oil recovery. About 60 gram positive bacteria isolated from soil contaminated with crude oil, near the crude oil storage tank in Tehran Refinery, Tehran, Iran. However, most of these studies have produced lipopeptide by one of the pure-culture microbes isolated in a laboratory. Among the isolates, heamolytic tests revealed two biosurfactant producers. The isolated strains were designated as C2, E1. By using morphological, biochemical and molecular biology tests (16 SrRNA), the strains identified as Bacillus licheniformis and Bacillus subtitlis, respectively. Emulsification activity and measurement of surface tension indicated that, the isolates were high producers of biosurfactant. The product of C2 and E1 is mainly lipopeptide. This product reduce surface tension from 65 to 30 mN/m. Emulsified activity of crude oil was 92% for C2 and 90 % in case of E1. This is the first report of indigenous Bacillus licheniformis and Bacillus subtilis from a soil contaminated with oil in an Iranian refinery with ability to produce biosurfactant.

Characterization of EPA’s 16 priority pollutant polycyclic aromatic hydrocarbons (PAHs) in tank bottom solids and associated contaminated soils at oil exploration and production sites in Texas

The purpose of this study was to determine the concentration and types of polycyclic aromatic hydrocarbons (PAHs), a group of environmentally toxic and persistent chemicals, at contaminated oil exploration and production (E&P) sites located in environmentally sensitive and geographically distinct areas throughout Texas. Samples of tank bottom solids, the oily sediment that collects at the bottom of the tanks, were collected from inactive crude oil storage tanks at E&P sites and hydrocarbon contaminated soil samples were collected from the area surrounding each tank that was sampled. All samples were analyzed for the 16 PAH priority pollutant listed by US EPA and for total petroleum hydrocarbons (TPH). The results demonstrate that overall average PAH concentrations were significantly higher in tank bottom solids than in contaminated soils. Total PAH concentrations decreased predictably with diminishing hydrocarbon concentrations; but the percent fraction of carcinogenic PAHs per total measured PAH content increased from approximately 12% in tank bottom solids to about 46% in the contaminated soils. These results suggest that the PAH content found in tank bottom solids cannot reliably be used to predict the PAH content in associated contaminated soil. Comparison of PAHs to conservative risk-based screening levels for direct exposure to soil and leaching from soil to groundwater indicate that PAHs are not likely to exceed default risk-based thresholds in soils containing TPH of 1% (10,000 mg/kg) or less. These results show that the magnitude of TPH concentration may be a useful indicator of potential risk from PAHs in crude oil-contaminated soils. The results also provide credibility to the 1% (10,000 mg/kg) TPH cleanup level, used in Texas as a default management level at E&P sites located in non-sensitive areas, with respect to PAH toxicity.

CFD study on mixing by coupled jet-impeller mixers in a large crude oil storage tank

This paper reports the results of a study on mixing by an impeller and a jet in the 19,000 m 3 crude oil storage tank of the Kermanshah Refinery of Iran. A three-dimensional modeling was carried out using an in-house computational fluid dynamics (CFD) code. The jet was placed theoretically next to the impeller and its effect on reducing the mixing time was investigated. Various jet outflow rates including: 33, 66, 132 and 264 m 3 h −1 were examined and the effect of the angle between the jet and the impeller on the mixing time for four setups was investigated. The results show when the angle between the jet and the impeller are 15°and 60°, the homogenization time is lower than that of other layouts. In addition, the homogenization progress by the selected jet-impeller layout was compared with the multiple-impellers setups. The results showed that a simple jet-impeller system operates in a more efficient way than even five-impeller setup.

06/01102 Characterization of paraffinic deposits in crude oil storage tanks using high temperature gas chromatography: Boukadi, A. et al. Applied Geochemistry, 2005, 20, (10), 1974–1983

06/01102 Characterization of paraffinic deposits in crude oil storage tanks using high temperature gas chromatography: Boukadi, A. et al. Applied Geochemistry, 2005, 20, (10), 1974–1983

Characterization of paraffinic deposits in crude oil storage tanks using high temperature gas chromatography

Problems related to the crystallization and deposition of heavy organic fractions during production, transportation and storage of crude oils can lead to considerable financial losses for the petroleum industry. The heavy organic fractions may include paraffins or waxes, resins, asphaltenes, and organometallic compounds that exist in crude oils in various quantities, states, and forms. The severity of the deposition problems varies widely and depends on factors such as the crude oil composition, operating conditions in the reservoir and production procedures. Problems associated with the solid deposits may be encountered anywhere in the production process from the reservoir to the refinery. In this paper, it is proposed to focus on production problems associated with certain fields in Tunisia. The problems manifested themselves through the accumulation of solid deposits in the storage tanks at a Tunisian terminal and originated from the mixtures of various crude oils transported to the terminal by pipeline. The principal analytical method for the characterization of the solids was high temperature gas chromatography following concentration of the wax fraction through a modification of the conventional acetone precipitation technique.