Study on the Safety of Restart of a Long-Term Unpigged Crude Pipeline

2010 ◽  
Author(s):  
Qing Miao
Keyword(s):  
Numerical Simulation ◽  
Crude Oil ◽  
Heat Loss ◽  
Paper Study ◽  
Wax Deposition ◽  
Oil Pipeline ◽  
Heat Preservation ◽  
Northeast Of China

A crude oil pipeline transporting heated Daqing crude in the Northeast of China had not carried out pigging for four years and the wax deposition in it was very serious. The existence of wax deposition layer decreased the heat loss of the crude in the pipeline during its normal running, but this did not mean it would also make the pipeline cool down slowly after the shutdown of the pipeline, that is, the wax deposition does not always benefit to the heat preservation of a long-term unpigged hot crude pipeline. So the restart safety of a long-term unpigged hot crude pipeline could not be derived directly from that of the same pipeline pigged before shutdown, even qualitatively. In this paper, study on the safety of the restart of a long-term unpigged crude pipeline is conducted based on numerical simulation and significant conclusions are drawn.

A Model for Predicting the Average Hydraulic Wax Deposition Thickness of a Long-Term Unpigged Crude Pipeline

2010 ◽  
Author(s):  
Qing Miao ◽  
Baoliang Jiang ◽  
Jianghua Tao ◽  
Sen Hu ◽  
Jianjun Liu
Keyword(s):  
Mathematical Model ◽  
Crude Oil ◽  
Wax Deposition ◽  
Oil Pipeline ◽  
Deposition Thickness ◽  
Northeast Of China ◽  
Statistical Results

A crude oil pipeline transporting Daqing crude in the Northeast of China had not been carried out pigging for four years. The wax deposition in it increased gradually over past four years. In this paper, from the operation data of the pipeline among the four years, the average hydraulic wax deposition thicknesses are calculated and analyzed statistically. Based on the results, the increment of the wax deposition in the long-term unpigged crude oil pipeline is concluded qualitatively and so a mathematical model for predicting the average hydraulic wax deposition thickness of such a pipeline is created. The physical meanings of the coefficients in the model are explained in the paper. Also, as an example for showing how to use this model, the statistical results on certain section of the pipeline are selected and the determination for the coefficients is introduced in detail.

scholarly journals Safety Study on Wax Deposition in Crude Oil Pipeline

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1572
Author(s):  
Bin Yao ◽  
Deyin Zhao ◽  
Zhi Zhang ◽  
Cheng Huang
Keyword(s):  
Crude Oil ◽  
Cloud Point ◽  
Freezing Point ◽  
Development Trend ◽  
Wax Deposition ◽  
Scanning Calorimetry ◽  
Long Distance ◽  
Wax Precipitation ◽  
Oil Pipeline ◽  
Precipitation Characteristics

The Shunbei crude oil pipeline is prepared to use the unheated transportation process to transport waxy crudes. However, the wax formation in the pipeline is unknown. In order to predict the wax deposition of the pipeline, the physical property experiment of Shunbei crude oil was carried out through field sampling. The density, freezing point, hydrocarbon composition, and viscosity–temperature characteristics of crude oil are obtained. The cloud point and wax precipitation characteristics of the crude oil were obtained using the differential scanning calorimetry (DSC) thermal analysis method. Then, the wax deposition rate of the pipeline was predicted by two methods: OLGA software and wax deposition kinetic model. Finally, the optimal pigging cycle of the pipeline was calculated on this basis. The results show that: Shunbei crude oil is a light crude oil with low wax content, a low freezing point, and a high cloud point. Comparing the OLGA simulation results with the calculation results of the Huang Qiyu model, the development trend of wax deposition along the pipeline was the same under different working conditions. The relative error of the maximum wax layer thickness was 6%, proving that it is feasible for OLGA to simulate wax deposition in long-distance crude oil pipelines. Affected by the wax precipitation characteristics of Shunbei crude oil, there was a peak of wax precipitation between the pipeline section where crude oil temperature was 9.31–13.31 °C and the recommended pigging cycle at the lowest throughput was 34 days in winter and 51 days in spring and autumn.

Study of Wax Deposition Rate in Waxy Crude Oil Pipeline

2013 ◽  
Vol 401-403 ◽  
pp. 891-894 ◽  
Author(s):  
Qing Lin Cheng ◽  
Xu Xu Wang ◽  
Xian Li Li ◽  
Wei Sun ◽  
Ling De Meng
Keyword(s):  
Crude Oil ◽  
Deposition Rate ◽  
Normal Operation ◽  
Wax Deposition ◽  
Waxy Crude Oil ◽  
Waxy Crude ◽  
Oil Pipeline ◽  
Oil Transportation ◽  
Different Seasons ◽  
Deposition Tendency

In waxy crude oil transportation process, wax crystals start to precipitate as the oil temperature drops to wax appearance point, and then form a network structure gradually which attaches to the wall. The problem of wax deposition seriously affects the normal operation of pipeline. Based on the wax deposition tendency coefficient method, combined with experimental data, the parameters related to wax deposition tendency coefficient is fitted, and the wax deposition rate equation of crude oil is determined finally. The variation law of wax deposition rate along the pipeline is analyzed, and the influence of different seasons and different throughput the on wax deposition rate is discussed subsequently.

Prediction of Wax Deposition in an Insulation Crude Oil Pipeline

2015 ◽  
Vol 33 (15-16) ◽  
pp. 1499-1507 ◽  
Author(s):  
Z. Hu ◽  
M. Wu ◽  
K. Hu ◽  
J. Liu
Keyword(s):  
Crude Oil ◽  
Wax Deposition ◽  
Oil Pipeline

NUMERICAL SIMULATION OF WAX DEPOSITION IN OIL PIPELINE SYSTEMS

2001 ◽  
Vol 19 (1-2) ◽  
pp. 143-156 ◽  
Author(s):  
E. Ramírez-Jaramillo ◽  
C. Lira-Galeana ◽  
O. Manero
Keyword(s):  
Numerical Simulation ◽  
Wax Deposition ◽  
Oil Pipeline ◽  
Pipeline Systems

GMS Numerical Simulation of Crude Oil Pollution Caused by Some Oil Pipeline Leak

2012 ◽  
Vol 488-489 ◽  
pp. 1076-1081
Author(s):  
Jian Hua Ye ◽  
Yu Feng Ren ◽  
Shu Kun Luo
Keyword(s):  
Numerical Simulation ◽  
Environmental Monitoring ◽  
Crude Oil ◽  
Groundwater Pollution ◽  
Prevention And Control ◽  
Groundwater Modeling ◽  
Oil Pollution ◽  
Oil Pipeline ◽  
Crude Oil Pollution ◽  
And Control

We have used Groundwater Modeling System (GMS) to numerical simulate the groundwater pollution migration caused by crude oil leak in the research regions. The result of the numerical simulation shows those 40 years after the crude oil leak, the contaminative area of pollutant reaches 46595 m3, and then the pollutant doesn’t arrive the pumping well. The density of the pollutants is less than 0.01mg/L. Therefore, we suggest that pipeline projects should make a specific effective plan for groundwater environmental monitoring for the sake of providing reference to institute relative countermeasure for prevention and control groundwater pollution.

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