Experimental study on wax deposition of highly paraffinic oil in intermittent gas-oil flow in pipelines

Oil-gas two phase wax deposition is a fairly common and open-ended question in flow assurance of multiphase transportation pipelines.This paper investigated the two main aspects of oil-gas two phase wax deposition layer:apparent thickness and crystal structure characteristics.A typical highly paraffinic oil in Bohai Sea,China,was used as the experimental material to investigate the wax deposition thickness in oil-gas two phase under the influence of different oil temperatures,superficial gas/liquid phase velocities and gas-oil ratios by using multiphase flow loop experimental device.Just as in the classical theory of wax molecular diffusion,it showed that wax deposition thickness of oil-gas two phase increased with increasing oil temperature.Analysis of the impact of different superficial phase velocities found that the actual liquid flow heat transfer and shear stripping was the gas phase dominant mechanisms determining wax deposit thickness.In addition,the crystal structure of the wax deposition layer was characterized with the help of small-angle X-ray scattering(SAXS)for different circumferential positions,flow rates and gas-oil ratios.The bottom deposition layer had a complex crystal structure and high hardness,which were subject to change over flow rate variations.Furthermore,the SAXS results provided evidence that the indirect effect of the actual liquid velocity modified by the gas phase was the main mechanism.Our study of the effect of gas phase on the wax deposition of oil-gas two phase will help shed light onto the mechanism by which this important process occurs.Our findings address a very urgent need in the field of wax deposition of highly paraffinic oil to understand the flow security of oilgas two phase that occurs easily in multiphase field pipelines.

Investigation of factors affecting on viscosity reduction of sludge from Iranian crude oil storage tanks

Crude oil is a kind of water/oil emulsion, which the oil phase consists of organic molecules with different molecular weights such as alkanes, paraffin, asphaltene, and resins. Due to the change in physicochemical conditions during the production, transportation, storage, and refining, heavier molecules can precipitate from crude oil. Thus, viscous sludge formed at the bottom of storage tanks can cause many problems including reduction of storage capacity of tank, oil contamination, corrosion, repair costs, environmental pollution, etc. The reduction of sludge viscosity can be achieved by reduction of its interfacial tension. In this study, different chemical and physical factors, influencing prepared emulsions（made of sludge, water and surfactant）, such as surfactants, solvents, temperature, pressure, and mixing conditions were investigated. Results showed that non-ionic surfactants（like bitumen emulsifier）, and solvents（such as mixed xylene, AW-400, and AW-402）, injection of additives, applying pressure, and mixing operations had a positive effect on reduction of emulsion viscosity. All experiments were carried out with sludge obtained from crude oil storage tanks at Kharg Island,Iran.

The Features of Acoustic Bathymetry of Sludge in Oil Storage Tanks

The features of acoustic bathymetry of sludge in crude oil tanks are considered. Different parameters of crude oil and sludge which are important for the selection of acoustic parameters such as sound speed, the acoustic impedances of “oil-sludge” boundaries and sound attenuation are analyzed and compared with experimental data. The main sources of errors of sludge volume estimation are discussed.

The Computer Aided Integrated Design and Analysis of Oil Tank in Vehicle

This paper creates 3D solid model and assembly of U RJ 92-6 oil tank and analyses its strength by integrated CAD/CAE/CAM software I-D EAS. Through integrated simulation in computer, design efficiency and quality of oil tank is greatly improved. Adopting integrated CAD/CAE/CAM software to carry out integrated research to equ ipment and products, we will be able to take overall analysis in aspects of 3-D solid modeling, pre-assembly and strength, etc., to realize non-paper designi ng and parallel designing. Problems can be found and settled during designing, w hich will increase designing efficiency and one-time success rate and realize o ptimum designing for products.

Sludge Pollution Control from Crude Oil Tank Cleaning

This study investigated the use of microbial analysis as a bioremediation option for remediating petroleum sludge, which is part of the waste stream generated in the petroleum industry. The aim is to reduce environmental burden caused by the discharge of untreated sludge. Sludge sample was cultured in other to isolate microorganisms for the sludge treatment. The selected strain of the organisms after screening were Aspergillus flavus, Aspergillus niger, Verticillus sp, Penicillum sp, and Microsporium audouinii. Bioreactors (labeled A, B, C, D and O) were designed for the treatment of petroleum sludge. These reactors contain 2.0 × 10-2 m3 of the diluted sludge samples and the isolated organisms for the treatment process. On a weekly basis, the control reactors received 1.5 × 10-3 m3 of fresh and saline water respectively. After 12 weeks of treatment, sludge physicochemical characteristics showed distinct variations. From the result, reactor D was the best in terms of remediating the sludge as compared to other reactors. Friedman non-parametric test was performed to check if the weeks of treatment affected the reduction of the total hydrocarbon content (THC) in the five reactors and also checked for significant differences in the THC after treatments. The drop in the THC of the treated sludge ranged from 56.0% to 67.3%. These results showed the possibility of enhanced biodegradation of petroleum sludge by hydrocarbon utilizing microorganisms (fungi).

Impact of Crude Oil Storage Tank Emissions and Gas Flaring on Air/Rainwater Quality and Weather Conditions in Bonny Industrial Island, Nigeria

This study investigated the effects of gaseous emissions from crude storage tank and gas flaring on air and rainwater quality in Bonny Industrial Island. Ambient air quality parameters, rainwater and weather parameters were collected at 60 m, 80 m, 100 m, 200 m and control plot for 4 weeks at the Bonny. Rainwater parameters were investigated using standard laboratory tests. Data analyses were done using Analysis of variance, pairwise t-test and Pearson’s correlation statistical tools. Results show that emission rates, volatile organic compound (VOC) noise and flare temperature decreased with increasing distance from flare points and crude oil storage tanks. Findings further revealed the emission rates varied significantly with distance away from the gas flaring point (F = 6.196;p = 0.004). The mean concentration of pollutants between gas flare site and crude oil storage tank showed that CO (0.02 ± 0.001 - 0.002 ±0.001), SPM (0.011 ± 0.001 - 0.01 ± 0.001), VOC (0.005 ± 0.001 - 0.01 ± 0.001) and NO2 (0.04 ± 0.001 - 0.005 ± 0.000) had significant variations (p > 0.05) with CO, O3 and NO2 having higher concentrations at the gas flare site while SPM, and VOC were higher around the crude oil storage tank site. Wind turbulence was higher around the gas flaring point (4.93 TKE) than the crude oil storage tank (4.55 TKE). Similarly, there was significant variation in the sun radiation, precipitation, and wind speed caused by gas flaring (1582.25 w/m2, 436.25 mm, 0.53 m/s) and crude oil storage tank (1536.25 w/m2, 3.91.41 mm, 0.51 m/s). There were also significant variations in flared temperature (F = 22.144;p = 0.001);NO2 (F = 8.250;p = 0.001), CO (F = 6.000;p = 0.004) and VOC (F = 5.574;p = 0.006) with distance from the gas flaring point. The variation in the rainwater parameters with distance from the gas flaring indicated significant variations in pH (F = 5.594;p = 0.006). The study showed that the concentration of VOC and particulates were high in the supposedly control area which is perceived to be safe for human habitation. Significant variations exist in emission rate (p = 0.015), flare temperature (p = 0.001), NO2 (p = 0.003), VOC (p = 0.001), noise (p = 0.041), hydrogen carbonate (p = 0.037) and chromium (p = 0.032) between the gas flaring and crude oil storage tank. Regular monitoring is advocated to mitigate the harmful effects of the pollutants.

DYNAMIC MODEL FOR OIL SLICK DISPERSION INTO A WATER COLUMN- A WINDDRIVEN WAVETANK EXPERIMENT

A dynamic experiment for oil dispersion into a water column was performed with a 21 m long, 0.5 m wide, and 1 m high wind-driven wave tank. At wind velocity between 6-12 m/s and with the oil slide kept constant (about 1 um), the rate of the oil content increase in the water column could be approximated from the difference between the dispersion rate (R) of the oil slick and the coagulation rate (R’) of the dispersed oil slick. Assuming the coagulation rate is directly proportional to the concentration of the water dispersed oil slick (i. e. R’ =KC),, the integral form of the dynamic model can be expressed as C=R*[1-exp(-K*t)]/K and parameters R and K can be regressed with a computer. The relative deviation of model results from the experimental data was mainly less than 10%. The oil slick dispersion rate (R) had exponential relationship with the wind velocity (V), and can be fitted with a formula R=A*(U+1)B.The fitted constant of the coagulation rate, K(0.8-3.0* 10-3 min-1) did not have significant

Analysis of Thermal Transfer of Reinforced Concrete Submarine Oil Tanks

-The temperature distributions obtained by different methods of analysis for solving thermal transfer of reinforced concrete (R. C.) submarine oil tanks (RCSOT), including flat wall method, cylinder wall method and finite element method, are compared with the experimental data of thermal transfer of RCSOT. The precision and scope of applicability of different methods are discussed. The principle for selecting analysis method for solving thermal transfer of RCSOT is given. The analytical and experimental temperature distributions show that the wall of RCSOT should consist of double walls and empty space between them should be filled with sand or other heat insulation materials to reduce the temperature difference of the wall and to prevent concrete from cracking.

A method for coastal oil tank detection in polarimetric SAR images based on recognition of T-shaped harbor

To automatically detect oil tanks in polarimetric synthetic aperture radar（SAR） images, a coastal oil tank detection method is proposed based on recognition of T-shaped harbor. First of all, the T-shaped harbor is detected to locate the region of interest（ROI） of oil tanks. Then all suspicious targets in the ROI are extracted by the segmentation of strong scattering targets and the classifier of H/α. The template targets are selected from the suspicious targets by the combination of a proposed circular degree parameter and the similarity parameter（SP） of the polarimetric coherency matrix. Finally, oil tanks are detected according to the statistics of the similarity parameter between each suspicious target and template targets in ROI. Polarimetric SAR data acquired by RADARSAT-2 over Berkeley and Singapore areas are used for testing. Experiment results show that most of the targets are correctly detected and the overall detection rate is close to 80%.The false rate is effectively reduced by the proposed algorithm compared with the method without T-shaped harbor recognition.

Optimization Model of Oil-Volume Marking with Tilted Oil Tank

In this paper, the relationship model between the oil volume and the vertically tilting parameter (α), the horizontally tilting parameter (β) and the displayed height of oil (h*) is first constructed with the tilted oil tank. Then, based on the data of the oil output volume at different time of day, an optimization model of oil-volume marking with tilted oil tank is established. Finally, parameters α = 2.2° and β = 3.05° are estimated by using nonlinear least squares method and the marking number of the tank-volume meter is given.

Multiplexing Technique Applied in the Optically Powered Oil-tank Detection System

The method of using multiplexing technique to realize the optically powered multiple detection system is presented. As this system adopted novel time and pulse width multiplexing techniques, reliable separation and error code correcting techniques, it realizes optically powered multiple channel and parameters detection, and successfully applied in the oil tanks for temperature, pressure, liquid level and reserve measurings.

The Research Application of 3D Laser Scanning Technology in the Deformation Detection of Large Cylindrical Oil Tank

In order to ensure the safety in using a large cylindrical storage tank,it is necessary to regularly detect its defonnatioii.The traditional total station method has high accuracy in determining the deformation,however,it has a low measxirement efficiency.Long-term observation means,there are more risks in the petrochemical plant,therefore,this paper proposes the usage of the 3D laser scanner,replacing the traditional total station to determine the defbnnation of a large cylindrical storage tank.The Matlab program,is compiled to calculate the point cloud data,while the tank deformation is analyzed from two different points which are,the local concave convex degree and the ovality degree.It is concluded that,the difference between the data obtained by 3D laser scanning,and total station is within the range of oil tank deformation limit,therefore,3D laser scanner can be used for oil tank deformation detection.

Evaluation of reservoir environment by chemical properties of reservoir water‒A case study of Chang 6 reservoir in Ansai oilfield,Ordos Basin,China

The Ordos Basin is the largest continental multi-energy mineral basin in China,which is rich in coal,oil and gas,and uranium resources.The exploitation of mineral resources is closely related to reservoir water.The chemical properties of reservoir water are very important for reservoir evaluation and are significant indicators of the sealing of reservoir oil and gas resources.Therefore,the caprock of the Chang 6 reservoir in the Yanchang Formation was evaluated.The authors tested and analyzed the chemical characteristics of water samples selected from 30 wells in the Chang 6 reservoir of Ansai Oilfield in the Ordos Basin.The results show that the Chang 6 reservoir water in Ansai Oilfield is dominated by calcium-chloride water type with a sodium chloride coefficient of generally less than 0.5.The chloride magnesium coefficients are between 33.7 and 925.5,most of which are greater than 200.The desulfurization coefficients range from 0.21 to 13.4,with an average of 2.227.The carbonate balance coefficients are mainly concentrated below 0.01,with an average of 0.008.The calcium and magnesium coefficients are between 0.08 and 0.003,with an average of 0.01.Combined with the characteristics of the four-corner layout of the reservoir water,the above results show that the graphics are basically consistent.The study indicates that the Chang 6 reservoir in Ansai Oilfield in the Ordos Basin is a favorable block for oil and gas storage with good sealing properties,great preservation conditions of oil and gas,and high pore connectivity.

动态热条件下原油罐储维温过程主要影响因素分析

掌握原油罐储维温过程主要影响因素,对原油库实现节能降耗目的起重要作用。在建立动态热条件下含蜡原油罐储维温过程三维理论模型的基础上,提出了加热盘管空间结构、周向效应对罐内对流传热的影响,划分了内、外因素影响区以及过渡区域;采用多元非线性回归的方法,建立不同季节边界位置主控影响因素模型,定量表征了罐边界油温与内、外因素之间的作用机制。结果表明:罐内大涡结构受无加热盘管区域局部湍涡影响,导致大涡结构向无盘管区域发生偏移。罐底低温区域受盘管周向效应影响较大,罐顶边界油品受内外因素影响大,形成最大厚度1.79 m的外界环境影响区;罐壁受保温层影响,只形成了内部维温热流影响区;冬季罐底形成了0.13 m的外界土壤影响区。

形状匹配的铁路油罐车罐口视觉定位方法

为了克服非均匀光照、车型以及摄像机安装位置等因素造成的罐口定位误差,提出了一种基于形状匹配的铁路油罐车罐口视觉定位方法。利用罐口为标准几何形状的特点,使用标准图像提取罐口边缘并进行形状拟合;将得到的轮廓形状作为图像识别模板,在待搜索图像中使用基于轮廓的归一化互相关查找目标;在搜索过程中对形状模板进行缩放,以兼容不同型号车型罐口;利用图像金字塔技术减小计算量,加快匹配速度。结果表明,所提出的方法满足误差要求,能够应用于工业现场。

延迟焦化装置酸性水除油脱焦粉技术改造

某石化公司1.2Mt/a延迟焦化装置在生产运行过程中存在分馏塔顶酸性水带油、带焦粉问题,在焦炭塔预热,污油、废渣回炼时尤为明显。分析原因为加工原料组成变化、酸性水量增加等导致分馏塔顶酸性水发生乳化、沉降时间不足,影响下游酸性水汽提装置的稳定运行。为解决以上问题,通过实施技术改造,在原分馏塔顶油水分离罐后增上一座酸性水沉降罐,将酸性水停留时间由1.10~2.56h增加至3.50~8.10h;在新增酸性水沉降罐后增加一台自动反冲洗过滤器,脱除酸性水中≥10μm的焦粉颗粒。技术改造实施完成投用后标定结果表明:酸性水中油含量从882mg/L下降至162mg/L,使油水充分分离,除油率达到81.63%;≥10μm的焦粉颗粒含量从463mg/L下降至9mg/L,脱除率达到98.06%,有效降低了酸性水油含量和焦粉颗粒含量,为下游酸性水汽提装置的稳定运行创造了条件。

550 kV大型主变压器储油柜油位异常的分析与处理

储油柜油位正常与否,直接关系到主变压器的安全稳定运行,针对某550 kV大型主变压器储油柜油位异常的问题,分析确定了储油柜内实际油位过高而油位计显示器显示偏低的原因,提出了一种简单快速的判断和处理方法,实际应用表明该方法的有效性。

油罐区电缆槽盒耐火性能测试方法研究

为提升油罐区电缆槽盒耐火性能测试的准确性和效率,提出一种以绝缘电阻作为判定指标的电缆槽盒耐火性能快速测试方法,并以试验的方式验证该方法的有效性和电缆槽盒的耐火性能。结果表明:测量电缆绝缘电阻值可以准确反映电缆槽盒在火灾时的失效过程,以107Ω作为电缆绝缘电阻失效判定指标可以准确反映电缆槽盒的耐火极限。

防止多仓汽车油罐车装错油的技术研究与应用

针对多仓汽车油罐车装油,司机接错进仓油管而装错油事故时有发生,从而导致加油站质量事故,影响企业信誉的问题。借助中石化首座智能油库科研项目的资金,开发了防止汽车油罐车装错油的技术设备。比较详细地介绍了该设备的组成、安装位置与要求、工作原理、改造原发油系统的两种方案及开票系统的修改内容及五个方面的验收要求,经改进完善,先后在笔者所在公司15座油库安装运行,效果良好,值得借鉴推广。

基于气体爆炸模拟系统(FLACS)模拟成品油储罐爆炸影响及灭火救援对策

以华中某成品油油库储罐为研究对象,模拟因雷击、静电等原因导致储罐内部着火,运用气体爆炸模拟系统(FLACS)软件分析储罐内部火灾爆炸后储罐的失效状态,指出储罐灭火救援存在的消防应急设备设施老化和故障、消防瞬时水量和灭火剂储备量难以满足灭火需求、消防水补给和事故污水超过油库承载能力以及缺乏新型灭火救援装备等问题,提出了相应对策:一是预防为主,建立消防设备设施定期维保和隐患排查治理机制;二是提前谋划,积极应对储罐火灾救援过程中的短板问题;三是合作共赢,与相关部门和企业建立应急联动机制。