Crude Oil Storage Research Articles

Flashing Losses Emission Evaluation from Crude Oil Storage Tanks

Evaporation is a natural phenomenon describing when a liquid turns into gas. Evaporation from roof storage tanks is a major source of product loss in the crude oil industry. Evaporation is a natural phenomenon describing when a liquid turns into a gas. A liquid will tend to evaporate depending on its vapor pressure. A liquid’s vapor pressure is dependent on the surface temperature and composition of the liquid. Evaporation losses should be minimized to help maximize company revenue, meet regulatory requirements, and reduce greenhouse gas. This flashing loss is measured by carrying out the extensive experimental test. Therefore, this paper covers how to estimate oil flashing losses emissions factor (FLEF) percentage for crude oil storage tanks by using the new equation technique to minimize human errors. This statistical technique is a linear association between possible variables to assess flashing loss percentage as a function of operating temperature, sample point height (H1), oil tank height (H2), gas/oil ratio, gas gravity and oil gravity. A good result was obtained from the proposed equation as compared with popular equations by using graphical and statistical exactness. Lastly, modeling testing is ensuring excellent agreement with laboratory work by using new different samples.

Study of extractants selectivity for extraction of organosulfur compounds from model solutions

Extraction of sulfur compounds from oil and petroleum products is a high priority task associated with tightening of the criteria of fuel quality control, negative impact of sulfur on the processing and storage of crude oil, environmental safety, as well as widespread use of organosulfur substances in different industries. The selectivity of several organic and inorganic extractants (methanol, N,N-dimethylformamide, acetonitrile, 15% NaOH, PEG 4000, PEG 200, diethylene glycol, monoethanolamine, dimethylacetamide, n -methylpyrrolidone) in relation to thiophene, dibenzothiophene, thiophenol, dodecanethiol and metilsulfide was studied for model solutions of organic sulfur compounds in n -heptane and n -octane. Extraction was carried out under static conditions. Sulfur content in the initial sample and in the sample after extraction was determined using an x-ray fluorescence analyzer SPECTROSCAN S. Chromatographic analysis of the samples was performed on an Agilent gas chromatograph with a mass-selective quadrupole detector. The selectivity of the studied extractants in relation to the studied groups of sulfur compounds was assessed through recovering (%) of a particular sulfur compound. It is shown that acetonitrile, N,N-dimethylformamide, dimethylacetamide and n -methylpyrrolidone are the most effective extractants for thiophene extraction. Methanol, N,N-dimethylformamide, acetonitrile, PEG200, diethylene glycol, monoethanolamine, dimethylacetamide and n -methylpyrrolidone are capable of extracting a wide range of organosulfur compounds from model solutions. Aqueous solutions of PEG 200 and PEG 4000 provide extraction less than 11% of organosulfur compounds, whereas 15% NaOH solution and a mixture of 50% NaOH:ethanol (1:2) are selective extractants for aliphatic mercaptans and provide up to 99% extraction of thiophenol and dodecanthiol, respectively. It was found that n -methylpyrrolidone, dimethylacetamide and N,N-dimethylformamide have the highest extraction capacity among the studied extractants. A series of studies gives ground to propose a possible extraction scheme for recovery of mercaptans from a mixture of organosulfur compounds.

Large-scale field test on abandoned deep anhydrite mine-out for reuse as crude oil storage – A case study

The reuse of abandoned anhydrite mine-outs has significant potential to reduce the cost and period of construction of crude oil storage facilities and provides a new option for exploiting underground space. Based on a case study of the Anhui Hengtai anhydrite mine located in East China, this study formulated a comprehensive field test program to investigate its tightness and stability and evaluate its feasibility for reuse as crude oil storage. Combining the field tests with laboratory tests, the underlying mechanism of interaction among anhydrite, water, and crude oil was revealed, and the stability and tightness of anhydrite mine-out during the storage of crude oil was evaluated. The results indicate that the anhydrite mine-out has good stability and tightness, which is not affected by the presence of crude oil. Additionally, the anhydrite has negligible effects on the crude oil quality; however, the presence of water reduces the strength of anhydrite rock, which has the potential to affect the stability and tightness of the mine-out. It is concluded that the anhydrite mine-out has the potential to be used as underground crude oil storage space, but the long-term contact between anhydrite rock and water should be avoided. This work is expected to benefit future underground space exploitation through reuse of mine-out.

Corrosion Strategy in Oil Field System

Crude oil is the main economic supply in many countries. Corrosion has been considered as the first fatal factor destroying the crude oil plants such as crude oil equipment, oil wells, separation vessels, storage tanks, and pipelines. This is the main reason encouraging many companies and researchers to develop new technological methods to manipulate corrosion. In this review, we discuss the types of corrosion, corrosion control methods (chemical and non -chemical methods), corrosion removal methods and corrosion monitoring process (direct and indirect measurement of corrosion). In addition some perspectives on SRB bacteria, types of inhibitors and gases removal methods were provided.

Selecting best painting colour for crude oil storage tanks exterior surface

The crude oil temperature, which highly influenced by solar heat and ambient temperature, has strong effects on the sludge formation and evaporative loss. Here, a numerical method has been presented for predicting the transient average crude oil temperature in storage tanks and the evaporative losses. Results show that the annual evaporative losses rise up to 125% if the tank exterior surface absorptivity is increased as 90% of the solar irradiation is absorbed. It was found that, the sludge height is reduced about 50 mm per months, when the absorptivity of the tank exterior surface is increased from a = 0.1 to a = 0.9 during winter. Considering the opposing effect of the in-tank crude oil temperature on the evaporative losses and sludge formation, the optimum absorptivity of the tank paint could be determined according to the minimal point in the summation curve of both losses. [Received: November 16, 2017; Accepted: May 16, 2018]

Selecting best painting colour for crude oil storage tanks exterior surface

The crude oil temperature, which highly influenced by solar heat and ambient temperature, has strong effects on the sludge formation and evaporative loss. Here, a numerical method has been presented for predicting the transient average crude oil temperature in storage tanks and the evaporative losses. Results show that the annual evaporative losses rise up to 125% if the tank exterior surface absorptivity is increased as 90% of the solar irradiation is absorbed. It was found that, the sludge height is reduced about 50 mm per months, when the absorptivity of the tank exterior surface is increased from á = 0.1 to á = 0.9 during winter. Considering the opposing effect of the in-tank crude oil temperature on the evaporative losses and sludge formation, the optimum absorptivity of the tank paint could be determined according to the minimal point in the summation curve of both losses. [Received: November 16, 2017; Accepted: May 16, 2018]

Long-Term Stability and Deformation Behaviour of Anhydrite Mine-Out for Crude Oil Storage

This paper describes a systematic method with high accuracy and efficiency to scientifically analyse the long-term stability and deformation behaviour of an anhydrite mine-out located in Anhui, South China and evaluate the feasibility of this mine-out as an underground crude oil storage space. Applying the particle swarm optimization algorithm, the parameters of Burgers creep model of anhydrite rock were obtained based on the uniaxial compressive creep test. Considering the results of numerical simulation, element safety factor (Esf) based on the Mohr’s strength theory was introduced and modified to quantificationally evaluate the long-term stability of cavern group. Combining field monitoring, the long-term deformation behaviour of the mine-out was analysed. The results show that the mine-out has good long-term stability and non-deformability. After 100 years of natural deformation, the vertical convergence deformation of the cavern is less than 500 mm, while lateral convergence deformation is less than 450 mm. The ground settlement is not more than 234 mm. The maximum loss rate of the space volume is no more than 5.38%, which is 4.75% under the condition of crude oil storage with 1.0 MPa internal pressure. Therefore, the mine-out has the potential to serve as an underground crude oil storage space.

Experimental investigation on the long-term interactions of anhydrite rock, crude oil, and water in a mine-out space for crude-oil storage

To evaluate the effectiveness of the usage of anhydrite mine-out spaces for crude-oil storage, this study conducted a long-term experimental investigation on the interaction of anhydrite rock with crude oil and water with varying pressure using pressurized reactors designed in this work. The physical and mechanical properties of anhydrite-rock samples for different test periods were studied to evaluate the effect of crude oil and water on the anhydrite-rock properties and reveal the action mechanism. The crude-oil property was tested after the experiments were completed to evaluate the effect of anhydrite on the crude oil. The results demonstrated that under long-term contact with varying pressure, the crude oil did not affect the physical and mechanical properties of anhydrite, and the anhydrite did not affect the crude-oil properties. However, the dissolution and recrystallization effects of water on the anhydrite induced reduction in the strength and stiffness of the anhydrite rock to a certain extent. Thus, water can potentially reduce the stability of an anhydrite mine-out space, which should be focused on when an anhydrite mine-out space is used for underground crude-oil storage.

Numerical simulation of thermal radiation distribution of large-scale crude oil storage tank

When the fire of a large-scale crude oil storage tank occurs, the fire source will emit large heat radiation which can induce not only serious economic losses, but also casualties. This paper investigated the influence of full-surface fire occurring in a crude oil storage tank on the adjacent tanks by numerical simulation based on the fire dynamic simulation software (FDS). Firstly, the combustion model of 105 m3 crude oil storage tank was constructed to reproduce the evolution behavior of the flame and smoke after the fire of the storage tank. The distributions of temperature and heat radiation value of adjacent storage tanks of crude oil storage tank were analyzed. The results show that a warning line with a radius of 57.77 m should be established to reduce the personnel and equipment damage caused by heat radiation when a full-surface fire occurs in the storage tank. This research can provide a technical basis and decisionmaking reference for the check computation of the fire-fighting capacity of fixed fire- fighting facilities, tactical arrangements of fire-fighting and rescue, and emergency rescue.

Heat transfer analysis of waxy crude oil under a new wide phase change partition model

The waxy crude oil is cooled and the waxy crystals form a grid structure after the shutdown, which leads to a very complicated heat transfer process. The degree of temperature drop of crude oil after shutdown directly determines the formulation of restart plan. How to accurately describe the phase transition heat transfer process of waxy crude oil based on the phase change of wax crystals is a hot issue in the field of crude oil storage and transportation. In this paper, the wax evolution process of crude oil was described, and a new wide phase transition partition model was proposed, with the governing equations being given for each sub-region. In the fuzzy zone of porous media, the Brinkmann-Forchheimer-Darcy seepage model was adopted. The iterative method was used to solve the discrete equations, and the solver adopted strong implicit method. The model and its solution method were verified by experiment. The breaking point was the index to judge the transition of crude oil from liquid phase to porous medium, and different breaking points of different kinds of crude oil correspond to different temperature ranges of porous media, so the influence of different breaking point temperature on heat transfer process was developed. Then, based on the model, the phase change heat transfer process was analyzed by using the change trajectory of the highest temperature point, and the transformation and influence of natural convection heat transfer process were discussed emphatically.

EIA Storage Announcements, Analyst Storage Forecasts, and Energy Prices

Exploring properties both of the EIA’s natural gas and crude oil storage announcements and of analyst forecasts of the EIA storage figures, we find that analyst storage forecasts bring additional information to the market beyond seasonal patterns and past storage flows and that the market promptly incorporates analyst forecasts into oil and gas prices prior to the EIA announcements. Analyst’s natural gas forecasts efficiently impound the available time-series information but crude oil forecasts do not. We further find that the price reaction to subsequent EIA natural gas storage announcements is contingent on the level of analyst forecast uncertainty as proxied by analyst forecast disagreement. Storage flows higher or lower than analysts had expected one week tend to be partially reversed the following week and analyst forecast dispersion regarding future forecasts increases following large forecast errors.

Numerical Simulation of Large Crude Oil Storage Tank Fire under Various Wind Speeds

In order to analyse the influence of the wind speed on the fire characteristics and hazards of large crude oil storage tanks, this paper used the fire dynamics simulation software FDS to simulate the fire of a large crude oil storage tank under various wind speeds. The fire characteristics such as flame, smoke and temperature distributions of the tank under different wind speeds were studied. The thermal effects on the adjacent tank and the way that the firefighters cool the hazardous area were discussed. The results show that with the increase of the wind speed, the flame, smoke and temperature distributions shift and spread downwind. When tank fire occurs, the firefighters should set up movable firefighting water gun near the dangerous area and lay fire water hose to the burning tank and its neighbours, which provides a good preparation for the subsequent firefighting operation near the burning tank.

Study of the influence of crude oil on the spontaneous combustion risk of sulfurized rust in crude oil tanks

Spontaneous combustion risk of sulfurized rust is the main cause of fire and explosion accidents during crude oil storage and transportation. In order to analyze the effect of crude oil on the thermal behavior of sulfurized rust, thermos-gravimetric analysis (TG) and differential scanning calorimeter (DSC) were used to evaluate the thermal behavior of the sulfurized rust, crude oil and their mixture. A deconvolution method is employed to analyze the complex thermal behavior of the mixture. The results indicate that the oxidation of crude oil can be separated into low temperature oxidation (LTO) and high temperature oxidation (HTO). The thermal behavior of mixture is similar to that of crude oil. It can be found that sulfurized rust may inhibit the decarboxylation reaction of crude oil in LTO while the sulfurized rust and crude oil promote each other in the HTO. With the increases of the mass percentage of crude oil, the onset temperature of mixture decreases and the reaction heat increases. The promotion effect is the most significant when the ratio of sulfurized rust and crude oil is 1:1.

Tracked Wall-Climbing Robot for Calibration of Large Vertical Metal Tanks

Large vertical metal tanks are the primary vessels for the storage and turnover of crude oil, and the accuracy of their capacity calibrations are of great significance. The optical reference line method (ORLM) is used for capacity calibration and is time-consuming, labor-intensive, and hazardous, because of the elevated work. This paper aims to present a robot to overcome the problems above. We propose a tracked wall-climbing robot (TWCR) with permanent magnetic adhesion tracks, a collapsible scale, and an optional shovel-like rust remover that enable the TWCR to move stably on tank surfaces and perform the ORLM. Two sets of field tests (internal ORLM and external ORLM) indicate that capacity calibration by the TWCR is time saving, convenient, and safe, in addition to being accurate and reliable.

Emission losses and dispersion of volatile organic compounds from tank farm of petroleum refinery complex.

Emission characteristics of volatile organic compounds (VOC) emitted from the tank farm of petroleum refinery were evaluated in this study in order to analyze for the potential impacts on health and odor nuisance problems. Estimation procedures were carried out by using the U.S.EPA TANK 4.0.9d emission model in conjunction with direct measurements of gas phase of each stored liquid within aboveground storage tanks. Results revealed that about 61.12% of total VOC emitted from the tank farm by volume were alkanes, in which pentane were richest (27.4%), followed by cyclopentane (19.22%), propene (19.02%), and isobutene (14.22%). Mostly of pentane (about 80%) were emitted from the floating roof tanks contained crude oil corresponded to the largest annual throughput of crude oil as compared with other petroleum distillates. Emission data were further analyzed for their ambient concentration using the AERMOD dispersion model in order to determine the extent and magnitude of odor and health impacts caused by pentane. Results indicated that there was no health impact from inhalation of pentane. However, predicted data were higher than the odor threshold values of pentane which indicated the possibility of odor nuisance problem in the vicinity areas of the refinery. In order to solve this problem, modification of the type of crude oil storage tanks from external floating roof to domed external floating roof could be significant success in reduction of both emissions and ambient concentrations of VOC from petroleum refinery tank farm.

An assessment of important SPECIATE profiles in the EPA emissions modeling platform and current data gaps

The United States (US) Environmental Protection Agency (EPA)'s SPECIATE database contains speciated particulate matter (PM) and volatile organic compound (VOC) emissions profiles. Emissions profiles from anthropogenic combustion, industry, wildfires, and agricultural sources among others are key inputs for creating chemically-resolved emissions inventories for air quality modeling. While the database and its use for air quality modeling are routinely updated and evaluated, this work sets out to systematically prioritize future improvements and communicate speciation data needs to the research community. We first identify the most prominent profiles (PM and VOC) used in the EPA's 2014 emissions modeling platform based on PM mass and VOC mass and reactivity. It is important to note that the on-road profiles were excluded from this analysis since speciation for these profiles is computed internally in the MOVES model. We then investigate these profiles further for quality and to determine whether they were being appropriately matched to source types while also considering regional variability of speciated pollutants. We then applied a quantitative needs assessment ranking system which rates the profile based on age, appropriateness (i.e. is the profile being used appropriately), prevalence in the EPA modeling platform and the quality of the reference. Our analysis shows that the highest ranked profiles (e.g. profile assignments with the highest priority for updates) include PM2.5 profiles for fires (prescribed, agricultural and wild) and VOC profiles for crude oil storage tanks and residential wood combustion of pine wood. Top ranked profiles may indicate either that there are problems with the currently available source testing or that current mappings of profiles to source categories within EPA's modeling platform need improvement. Through this process, we have identified 29 emissions source categories that would benefit from updated mapping. Many of these mapping mismatches are due to lack of emissions testing for appropriate source categories. In addition, we conclude that new source emissions testing would be especially beneficial for residential wood combustion, nonroad gasoline exhaust and nonroad diesel equipment.

Occurrence and Characterization of Paraffin Wax Formed in Developing Wells and Pipelines

Deposition and precipitation of paraffin wax in pipelines are major problems in the production, transfer, storage, and processing of crude oil. To prevent complete clogging, it is necessary to minimize and remove deposited wax in pipelines and tubing. Significant research has been done addressing the mechanisms of wax formation and its composition. In this review, the status of research and perspectives on the occurrence and characterization of the paraffin wax that forms in crude oil developing wells and pipelines has been critically reviewed. Several approaches for detecting paraffin wax and managing wax formation damage during oil recovery were discussed. This review also highlighted the effects of temperature and crude oil type on wax formation.

Preparation of Fe-char catalyst from tank cleaning oily sludge for the catalytic cracking of oily sludge

As a hazardous organic waste, the disposal and utilization of oily sludge discharged from crude oil storage tank have received widespread attention. In this study, a novel method was proposed that Fe-char was prepared from oily sludge and was further applied to the catalytic cracking of heavy oil in oily sludge. The char exhibited a porous structure and the inherent iron oxides were directly reduced to metallic iron (Fe°) at 900°C after carbonization. The catalytic effects of the char prepared at 600 °C (Char600) and 900 °C (Char900) were compared in terms of oil conversion efficiency and gas yield. The oil conversion efficiency over Char900 was higher than that over Char600 at 600 °C (90.2% vs. 80.1%). Meanwhile, the polyaromatics in the oil product were cracked into monocyclic aromatics and the H2 and CO yields were increased significantly by using Char900, indicating that Fe° exhibited better catalytic performance for the cracking of hydrocarbons than iron oxides. The effects of catalytic temperatures (600–800 °C) on the performance of Char900 were also investigated. At 800 °C, the oil conversion efficiency reached the highest (95.8%) and the CO yield was 9.5 times higher than that under uncatalyzed conditions. Overall, the catalytic effect of Char900 can be attributed to the combined effects of char and Fe°. Char not only provided a porous surface for the adsorption of hydrocarbons, but also can react with moisture in the oily sludge through water gas reactions, enhancing the production of syngas. Moreover, Fe° played a significant role as a catalytic medium for promoting the hydrocarbons reforming and water gas shift (WGS) reactions.

Assessing the water-sealed safety of an operating underground crude oil storage adjacent to a new similar cavern – A case study in China

Siting a new underground water-sealed crude oil storage adjacent to an existing one is a potential way to increase the capacity of strategic energy storage. The study presented herein is a comprehensive case study to assess the water-sealed safety on this topic using monitoring data and numerical analyses. A three-dimensional geo-hydrological model was built based on a specific project calibrated using field monitoring data. The influence of the new construction on the water-sealed safety of the operating cavern was examined with numerical models by considering the effects of the layout of the new cavern. Three indicators were used to quantitatively assess the water-sealed safety of the operating cavern. The result shows that it is feasible to set a storage cavern adjacent to an operating one. The safety separation distance between two projects without a vertical water curtain can be set to 200 m. In addition, vertical water curtain was discussed to shorten the safety separation distance in practical (e.g. with site conditions limitation). The achieved results can be used to guide the design and construction of similar projects.

A novel method for the separation of high-molecular-weight saturates from paraffinic petroleum based samples

The precise chromatographic isolation of saturates is a common problem of the characterization of highly paraffinic petroleum based samples. Incomplete elution of high-molecular-weight saturates (HMWS) or contamination of saturates by aromatics can occur when alumina or silica gel are used to separate highly paraffinic samples. Here, we present a precise, fast and simple method for the quantitative isolation of HMWS from samples of highly paraffinic crude oils, crude oil deposits, high-boiling petroleum distillates, distillation residues and waxes. The method is based on a direct chromatographic elution of HMWS with n-heptane at 80 °C on a column packed with silica gel modified with silver nitrate. The pre-separation of asphaltenes from samples is not necessary. This allowed for a quantitative elution of all present HMWS (up to C100) with no contamination by aromatics. As an example of a practical application to benefit from this efficient hydrocarbon fractionation procedure, is the analysis of crude oils and deposits. A detailed knowledge of the content of high-molecular-weight n-alkanes in these samples can help to prevent problems during crude oil transport and storage.