Wax deposition rate model for heat and mass coupling of piped waxy crude oil based on non-equilibrium thermodynamics

Wax deposition rate model for heat and mass coupling of piped waxy crude oil based on non-equilibrium thermodynamics

Crude oil

Petroleum pipelines

Petroleum transportation

Pipeline terminals

Entropy

Molecules

Mass transportation

Diffusion in liquids

Thermodynamic stability

Diffusion in solids

Statistical mechanics

Crystallography

Deposition rates

Differential equations

In this paper, wax deposition in waxy crude oil transportation process was regarded as an irreversible process. Based on the entropy production rate equations, the linear phenomenological equations for the diffusion of wax molecules were derived by using the theory and method of non-equilibrium thermodynamics and heat-mass transfer. Combined with the mass and energy conservation laws, the differential equations of heat and mass transfer in the process of pipeline transportation were established, and the molecular diffusion rate of dissolved wax was solved. On the basis of this, the mathematical model of actual wax deposition rate was established by considering the attachment process and scouring process of the wax molecules. Taking an oil pipeline in Daqing as an example, the change law and influencing factors of the wax molecular diffusion coefficient, the wax deposition rate, and the net wax deposition rate were studied by numerical simulation. The wax deposition rate test results of the laboratory loop test were compared with the theoretical calculation results in order to analyze the accuracy and the adaptability of heat and mass coupling mechanism and to provide a theoretical basis for further study of wax deposition in the process of waxy oil pipeline transportation. 2017 Taylor & Francis.

259-269

2

39

Journal of Dispersion Science and Technology

2018

Liu, Yang

Pan, Chenlin

Cheng, Qinglin

Wang, Bing

Wang, Xuxu

Gan, Yifan

journalArticle

1932691

10.1080/01932691.2017.1312432