scholarly journals Research on Design Method for Thermal Insulation of Oil Pipeline in Permafrost Regions

2020 ◽  
Vol 165 ◽  
pp. 01016
Author(s):  
Dongyuan Wang ◽  
Zifeng Zhao ◽  
Qiuxia Tan ◽  
Jian Yang
Keyword(s):  
Temperature Field ◽  
Thermal Insulation ◽  
Design Method ◽  
Maximum Amount ◽  
Freezing Damage ◽  
Strain Criterion ◽  
Oil Pipeline ◽  
Oil Pipelines ◽  
The Status ◽  
Permafrost Regions

The most important problems encountered in the design and operation of oil pipelines in permafrost regions are frost heaving and thawing settlement. In this paper, we conducted an investigation and analysis on the status of freezing damage of the operating oil pipelines. Based on the investigation and research, we calculated the temperature field of the oil pipeline and analysed the thawing ability under the conditions of the strain criterion. Finally, we proposed a design method for pipeline insulation and the maximum amount of thawing displacement that the pipeline can withstand. It has certain guiding significance for the thermal insulation design of oil pipelines in permafrost regions.

Establishment and Application of the Pipeline Monitoring System in Permafrost Regions in China

2020 ◽  
Author(s):  
Jianping Liu ◽  
Pengchao Chen ◽  
Hong Zhang ◽  
Baodong Wang ◽  
Xiaoben Liu
Keyword(s):  
Temperature Field ◽  
Soil Temperature ◽  
Monitoring System ◽  
Field Monitoring ◽  
Measurement Unit ◽  
Displacement Monitoring ◽  
Ground Displacement ◽  
Oil Pipeline ◽  
Strain Monitoring ◽  
Permafrost Regions

Abstract Buried pipelines in permafrost regions are inevitably subjected to some typical geohazards, such as frost heave, thaw settlement and thaw slumping. The bending or/and longitudinal strains will be induced in pipe under these types ground movement, which is the potential cause of weld joint rupture. Thus, in order to prevent pipe failure, a comprehensive monitoring system was designed and used in the Mohe-Daqing oil pipeline in the permafrost region in northeast China. The Mohe-Daqing oil pipeline is built for importing oil from Russia and its north part of 440km lays in permafrost. The monitoring system includes soil temperature field monitoring system, ground displacement monitoring system and pipe strain monitoring system. The soil temperature field monitoring system, which uses fiber brag grating sensors, can monitor the distribution of surrounding soil temperature in radial direction of pipe in order to detect the change of active ring of permafrost. The ground displacement monitoring system, which is based on a total station, can discover any subsidence or heave of the pipe itself and the embankment along the pipeline. The pipe strain monitoring system, which includes pipe stress monitoring system based on fiber brag grating sensors and inertial measurement unit (IMU) mapping, can inspect the real-time change of pipe stress and the bending strain periodically respectively. Using the comprehensive monitoring system, the important parameters that affect pipeline integrity such as pipeline temperature, stress, strain and displacement of Mohe-Daqing oil pipeline can be supervised timely and effectively. And the accuracy and reliability of the monitoring system have been verified in practical application. In this paper, detail about how these systems are designed and installed on the Mohe-Daqing oil pipeline is elucidated and the monitoring data is analyzed. Through these data, the present mechanical situation of Mohe-Daqing oil pipeline is safe, but the long-term change is critical because of the soaring oil temperature that is far high than the design temperature. The monitoring system is of great significance to ensure the safe operation of Mohe-Daqing pipeline and can provide reference for the pipeline operation in permafrost areas.

Thermal Characteristics Simulation of the Commissioning Process for New Buried Heated Oil Pipelines

2011 ◽  
Vol 301-303 ◽  
pp. 610-616 ◽  
Author(s):  
Guo Qun Chen ◽  
Ming Hua Zhao ◽  
Bo Xu
Keyword(s):  
Temperature Field ◽  
Crude Oil ◽  
Thermal Characteristics ◽  
Hot Water ◽  
Waxy Crude Oil ◽  
Long Distance ◽  
Warm Up ◽  
Oil Pipeline ◽  
Heated Oil ◽  
Oil Pipelines

For a new buried heated oil pipeline, the temperature field of the surrounded soil is natural. Therefore the temperature is usually low in this case. For the waxy crude oil whose pour point is higher than the ground temperature, if the new pipeline transports such oil directly after heating, crude oil may gel in pipeline because its temperature decrease dramatically due to heat exchange between the fluid and the surrounded soil. Hence, in practical situation hot water is often used to warm up the pipelines for most of the new long-distance buried pipelines. Crude oil transportation is determined after the soil temperature field around the pipeline is sufficiently high and the inlet water temperature meets the requirement.

Using clusterization principles for the selection of repair sections of main oil pipelines based on diagnostic data

2011 ◽  
Vol 8 (1) ◽  
pp. 201-210
Author(s):  
R.M. Bogdanov
Keyword(s):  
Cluster Analysis ◽  
Defect Density ◽  
Density Variation ◽  
Distance Functions ◽  
Oil Pipeline ◽  
Oil Pipelines ◽  
Classification Of Images ◽  
Main Oil Pipeline ◽  
Selection Of

The problem of determining the repair sections of the main oil pipeline is solved, basing on the classification of images using distance functions and the clustering principle, The criteria characterizing the cluster are determined by certain given values, based on a comparison with which the defect is assigned to a given cluster, procedures for the redistribution of defects in cluster zones are provided, and the cluster zones parameters are being changed. Calculations are demonstrating the range of defect density variation depending on pipeline sections and the universal capabilities of linear objects configuration with arbitrary density, provided by cluster analysis.

scholarly journals Evolution regularity of temperature field of active heat insulation roadway considering thermal insulation spraying and grouting: A case study of Zhujidong Coal Mine, China

2021 ◽  
Vol 40 (1) ◽  
pp. 151-170
Author(s):  
Weijing Yao ◽  
Happiness Lyimo ◽  
Jianyong Pang
Keyword(s):  
Sensitivity Analysis ◽  
Temperature Field ◽  
Thermal Insulation ◽  
Wall Temperature ◽  
Heat Insulation ◽  
Surrounding Rock ◽  
Rock Temperature ◽  
Grouting Materials ◽  
Zone Radius ◽  
Thermal Conductivities

Abstract To study the active heat insulation roadways of high-temperature mines considering thermal insulation and injection, a high-temperature −965 m return air roadway of Zhujidong Coal Mine (Anhui Province, China) is selected as a prototype. The ANSYS numerical simulation method is used for the sensitivity analysis of heat insulation grouting layers with different thermal conductivities and zone ranges and heat insulation spray layers with different thermal conductivities and thicknesses; thus, their effects on the heat-adjusting zone radius, surrounding rock temperature field, and wall temperature are studied. The results show that the tunneling head temperature of the Zhujidong Mine is >27°C all year round, consequently causing serious heat damage. The heat insulation circle formed by thermal insulation spraying and grouting can effectively alleviate the disturbance of roadway airflow to the surrounding rock temperature field, thereby significantly reducing the heat-adjusting zone radius and wall temperature. The decrease in the thermal conductivities of the grouting and spray layers, expansion of the grouting layer zone, and increase in the spray layer thickness help effectively reduce the heat-adjusting zone radius and wall temperature. This trend decreases significantly with the ventilation time. A sensitivity analysis shows that the use of spraying and grouting materials of low thermal conductivity for thermal insulation is a primary factor in determining the temperature field distribution, while the range of the grouting layer zone and the spray layer thickness are secondary factors. The influence of the increased surrounding rock radial depth and ventilation time is negligible. Thus, the application of thermal insulation spraying and grouting is essential for the thermal environment control of mine roadways. Furthermore, the research and development of new spraying and grouting materials with good thermal insulation capabilities should be considered.

scholarly journals Perceptions of midwives on shortage and retention of staff at a public hospital in Tshwane District

Curationis ◽  
2019 ◽  
Vol 42 (1) ◽  
Author(s):  
Mosehle S. Matlala ◽  
Thanyani G. Lumadi
Keyword(s):  
Decision Making ◽  
Design Method ◽  
Quality Care ◽  
Sampling Technique ◽  
The Status ◽  
Generic Qualitative ◽  
Tertiary Hospitals ◽  
Decision Making Processes ◽  
Group Interviews ◽  
The Impact

Background: Midwifery is the backbone of women and child healthcare. The shortage of staff in maternity units is a crisis faced by many countries worldwide, including South Africa.Objectives: This study aims to explore the perceptions of midwives on the shortage and retention of staff at a public institution.Method: The study was conducted at one of the tertiary hospitals in Tshwane District, Gauteng Province. A total of 11 midwives were interviewed through face-to-face and focus group interviews. An explorative, descriptive generic qualitative design method was followed, and a non-probability, purposive sampling technique was used. Thematic coding analysis was followed for analysing data.Results: The impact of shortage of midwives was reported to be directly related to poor provision of quality care as a result of increased workload, leading to low morale and burnout. The compromised autonomy of midwives in the high obstetrics dependency units devalues the status of midwives.Conclusion: Midwives are passionate about their job, despite the hurdles related to their day-to-day work environment. They are demoralised by chronic shortage of staff and feel overworked. Staff involvement in decision-making processes is a motivational factor for midwives to stay in the profession. The midwives need to be in the centre of the decision-making processes related to their profession. The revision of the scope of practice and classification of midwifery profession away from general nursing complex by the South African Nursing Council (SANC) could place midwifery in its rightful status.

Heat Effect Analysis of Buried Oil Pipeline in the Qinghai-Tibet Plateau

2014 ◽  
Vol 501-504 ◽  
pp. 211-217
Author(s):  
Wei Bo Liu ◽  
Wen Bing Yu ◽  
Xin Yi ◽  
Lin Chen
Keyword(s):  
Temperature Field ◽  
Frozen Soil ◽  
Operating Conditions ◽  
Tibet Plateau ◽  
Soil Mechanic ◽  
Insulation Layer ◽  
Effect Analysis ◽  
Oil Pipeline ◽  
Permafrost Table ◽  
Qinghai Tibet Plateau

The Geermu-Lasa oil pipeline was located in the Qinghai-Tibet Plateau permafrost regions. The building and operating of pipeline will change the temperature field of soil around it, which can lead to changes of frozen soil mechanic properties, and this will induces deformation or even fracture of pipeline. These phenomena will affect the normal transportation of oil. In this paper, temperature field around the pipelines were analyzed due to different pipe diameters and different insulation layer thicknesses in the way of finite element method. The rule of thawing and freezing of soil around the pipeline in an annual cycle was obtained. Artificial permafrost table variations under the pipeline were also obtained due to different operating conditions. For 30cm diameter pipeline with 7cm insulation layer, its artificial permafrost table depth change value is just 0.48m after 30-year running. These analysis results can provide references to the construction of the new Geermu-Lasa oil pipeline.

Modified equations for hydraulic calculation of thermally insulated oil pipelines for the case of a power-law fluid

2021 ◽  
pp. 388-395
Author(s):  
Марат Замирович Ямилев ◽  
Азат Маратович Масагутов ◽  
Александр Константинович Николаев ◽  
Владимир Викторович Пшенин ◽  
Наталья Алексеевна Зарипова ◽  
...  
Keyword(s):  
Power Law ◽  
Analytical Calculation ◽  
High Viscosity ◽  
Hydraulic Calculation ◽  
Flow Index ◽  
Pipeline System ◽  
Power Law Fluid ◽  
Simplified Approach ◽  
Oil Pipeline ◽  
Oil Pipelines

Теплогидравлический расчет неизотермических трубопроводов является наиболее важным гидравлическим расчетом в рамках решения задач обеспечения надежности и безопасности работы нефтепроводной системы. Для практических расчетов применяются формулы Дарси - Вейсбаха и Лейбензона. При этом в ряде случаев (короткие теплоизолированные участки, поверхностный обогрев нефтепроводов) можно использовать упрощенный подход к расчету, пренебрегая изменением температуры или учитывая температурные поправки. В настоящее время формулы для аналитического расчета движения высоковязких нефтей в форме уравнения Лейбензона получены только для ньютоновской и вязкопластичной жидкостей. Для степенной жидкости соответствующие зависимости отсутствуют, расчет ведется с использованием формулы Дарси - Вейсбаха. Целью настоящей статьи является представление формулы Дарси - Вейсбаха для изотермических течений степенной жидкости в форме уравнения Лейбензона. Данное представление позволит упростить процедуру проведения аналитических выкладок. В результате получены модифицированные уравнения Лейбензона для определения потери напора на участке нефтепровода в диапазоне индекса течения от 0,5 до 1,25. В указанном диапазоне относительное отклонение от результатов расчетов с использованием классических формул Метцнера - Рида и Ирвина не превышает 2 %. The thermal-hydraulic calculation of non-isothermal pipelines is the most important hydraulic calculation in the framework of solving the problems of ensuring the reliability and safety of the oil pipeline system. For practical calculations, the Darcy - Weisbach and Leibenson formulas are used. Moreover, in a number of cases (short heat-insulated sections, surface heating of oil pipelines), a simplified approach to the calculation can be used, neglecting temperature changes or taking into account temperature corrections. At present, formulas for the analytical calculation of the motion of high-viscosity oils in the form of the Leibenson equation have been obtained only for Newtonian and viscoplastic fluids. For a power-law fluid, there are no corresponding dependences; the calculation is carried out using the Darcy - Weisbach formula. The purpose of this article is to present the Darcy - Weisbach formula for isothermal flows of a power-law fluid in the Leibenzon form, which will simplify the procedure for performing analytical calculations. The modified Leibenzon equations are obtained to determine the head loss in the oil pipeline section in the range of the flow index from 0.5 to 1.25. In the specified range, the relative deviation from the results of calculations using the classical Metzner - Reed and Irwin formulas does not exceed 2 %.

scholarly journals Study on Optimizing Operation of Preheating Commissioning for Waxy Crude Oil Pipelines

2014 ◽  
Vol 6 ◽  
pp. 894256
Author(s):  
Jian Zhang ◽  
Yi Wang ◽  
Xinran Wang ◽  
Handu Dong ◽  
Jinping Huang ◽  
...  
Keyword(s):  
Crude Oil ◽  
Outlet Temperature ◽  
Fluid Temperature ◽  
Governing Equations ◽  
Waxy Crude Oil ◽  
Waxy Crude ◽  
Oil Pipeline ◽  
Single Station ◽  
Oil Pipelines ◽  
Volume Method

A mathematical model is established for the preheating commissioning process of waxy crude oil pipelines. The governing equations are solved by the finite volume method and the finite difference method. Accordingly, numerical computations are made for the Niger crude oil pipeline and the Daqing-Tieling 3rd pipeline. The computational results agree well with the field test data. On this basis, fluid temperature in the process of the preheating commissioning is studied for single station-to-station pipeline. By comparing different preheating modes, it is found that the effect of forward preheating is the best. Under different preheating commissioning conditions, the optimal combination of outlet temperature and flow rate is given.

scholarly journals MoIncreasing The Efficiency of the Systems of Overhead Oil Pipelines Equipped with Electric Heating

2021 ◽  
Vol 135 (4) ◽  
pp. 50-55
Author(s):  
A. K. Nikolaev ◽  
◽  
N. A. Zaripova ◽  
V. V. Pshenin ◽  
◽  
...  
Keyword(s):  
Pressure Drop ◽  
Thermal Insulation ◽  
Remote Monitoring ◽  
Electric Heating ◽  
Leak Detection ◽  
Robotic Device ◽  
Detection Systems ◽  
Oil Pipelines ◽  
Significant Temperature ◽  
Technical Solutions

Nowadays, there are several technical solutions for remote monitoring of the parameters of pipelines in thermal insulation. The analysis of such solutions is presented in the article. The authors proposed an algorithm for calculating the pressure drop in a stopped pipeline, suitable for determining leaks. The value of the algorithm increase due to the possibility of its use for calculating the parameters of hydrotesting in conditions of significant temperature differences. This implies the possibility of integrating the obtained relationships into parametric leak detection systems. The article also considers different proposals for increasing the efficiency of using pipelines equipped with SKIN systems. The authors proposed a diagnostic robotic device capable of overcoming complex sections of SKIN systems, as well as monitoring the system along its entire length.

Sign in / Sign up

Export Citation Format

Share Document