Predicting Mixing Volumes in Serial Transport in Pipelines

Trailing oil is the tail section of contamination in oil pipelines. It is generated in batch transportation, for which one fluid, such as diesel oil follows another fluid, such as gasoline, and it has an effect on the quality of oil. This paper describes our analysis of the formation mechanism of trailing oil in pipelines and our study of the influence of dead-legs on the formation of trailing oil. We found that the oil replacement rate in a dead-leg is exponentially related to the flow speed, and the length of the dead-leg is exponentially related to the replacement time of the oil. To reduce the amount of mixed oil, the main flow speed should be kept at about 1.6 m/s, and the length of the dead-leg should be less than five times the diameter of the main pipe. In our work, the Reynolds time-averaged method is used to simulate turbulence. To obtain contamination-related experimental data, computational fluid dynamics (CFD) software is used to simulate different flow rates and bypass lengths. MATLAB software was used to perform multi-nonlinear regression for the oil substitution time, the length of the bypass, and the flow speed. We determined an equation for calculating the length of the trailing oil contamination produced by the dead-leg. A modified equation for calculating the length of the contamination was obtained by combining the existing equation for calculating the length of the contamination with new factors based on our work. The amounts of contamination predicted by the new equation is closer to the actual contamination amounts than predicted values from other methods suggested by previous scholars.

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Section: Introductionmentioning

confidence: 99%

Formation Mechanism of Trailing Oil in Product Oil Pipeline

Liu

Hong-jun

et al. 2018

Processes

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“…As a motivation for this study, there is the characterization of the interface contamination formed between batch transfers of two different fluids and its spread along the flow. Petroleum transport through long pipelines is an example of application for that (Rachid et al, 2002). The bulk properties were considered constant, the constitutive equations for a Carreau fluid were employed (Eq.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…This kind of phenomenon finds application in many subjects in engineering. In petroleum engineering, modeling and simulation of mixture volumes that arise between batch transfers of petroleum fractions in multiproduct pipelines has been studied by Rachid et al (2002). In environmental engineering, problems of liquid effluent dispersion in lakes and rivers are common.…”

Section: Introductionmentioning

confidence: 99%

Finite element approximation for single-phase multicomponent flows

Franceschini

Frey

2005

Mechanics Research Communications

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“…The governing equation of the model is a nonlinear boundary value problem, which is solved by coupling the finite element method with Newton method. Rachid et al [14,15] proposed a new mixing calculation model. They found that the flow direction had no effect on the mixing volume with the same change in pipe diameter.The above research shows that the viscosity difference is the main factor that causes the tail of contamination, but these studies do not consider the special situations,such as dead-legs in a valve chamber, and are not closely integrated with practical engineering.…”

Section: Introductionmentioning

confidence: 99%

Research on Formation Mechanism of Trailing Oil in Product Oil Pipeline

Liu¹,

Li²,

Cai³

et al. 2018

Preprint

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Trailing oil is the tail section of contamination. There are two main reasons for the formation of trailing oil, one is the effect of laminar flow boundary layer, the other is the outflow of the preceding batch remained in the dead-legs. In the batch transportation of refined oil, under the action of viscous force, the preceding batch forms laminar boundary layer near the pipe wall and stays on the pipe wall, resulting in the phenomenon of contamination trailing and formation of trailing oil. When oil passes through the valve chamber of the oil transportation station, dead-leg will be formed. Due to gravity and convection diffusion, preceding batch flowing from dead-legs will form trailing oil in the pipeline. The phenomenon of trailing oil exists in the process of batch transportation, which will have an effect on the quality of oil. In this paper, Reynolds time-averaged method is used to simulate turbulence.Computational Fluid Dynamics(CFD) software is used to simulate different flow rates and bypass lengths to obtain contamination-related experimental data.Matlab software is used to perform multi-nonlinear regression for the oil substitution time, the length of the bypass and the flow rate. The formula for calculating the length of the trailing oil produced by the dead-leg is obtained. The modified formula for calculating the length of the contamination is obtained by combining the existing formula for calculating the length of the contamination.

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Predicting Mixing Volumes in Serial Transport in Pipelines

Cited by 22 publications

References 8 publications

Formation Mechanism of Trailing Oil in Product Oil Pipeline

Formation Mechanism of Trailing Oil in Product Oil Pipeline

Finite element approximation for single-phase multicomponent flows

Research on Formation Mechanism of Trailing Oil in Product Oil Pipeline

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