The Research On Generalized Exergy Transfer Characteristic Of Crude Oil Pipeline Process

In our country most of crude oil produced are the high pour-point or the viscous heavy crude and pipeline transportation is the main mode to transport crude oil.So the operation energy consumption and oil transportation cost are very high.It is of great theoretical significance for energy saving and consumption reduction to analyze the process of waxy crude oil pipeline transportation from the thermodynamic point of view and to use exergy transfer and conversion theory to analyze the essence of energy utilization in the process of pipeline transportation.Firstly,according to the actual transmission phenomenon of engineering practice,the thermodynamic force and flow of transfer process are generalized and the concept and classification of exergy are proposed.By using the concept of general energy state function and the method of correlation tensor analysis,the exergy transfer equation are deduced.Based on these equations,the generalized transfer and transformation relation of exergy are summarized.Secondly combined the basic balance equations of crude oil pipeline process with the basic equation group of exergy,the transfer equations of heat exergy,pressure exergy and diffusion exergy are solved.Then the transfer and transformation law and characteristics of different kinds of exergy are discussed.Thirdly on the basis of exergy transfer thermodynamics theory and exergy dynamic equations,the mathematical expressions of pipeline exergy transfer coefficient and exergy flow density are derived,according to the exergy transfer thermodynamics equation of crude oil pipeline process in this paper.The change low and influencing factors are also presented.Meanwhile taking an oil pipeline in oil field as an example,transfer characteristics of different exergy along the pipeline under different conditions are studied.At last,based on the field synergy principle suitable for general process,the issue is proposed about exergy transfer process for multi-potential fields.By analyzing the potential field of crude oil pipeline process and combining the theory of exergy transfer phenomenological law of multi-potential fields,the exergy transfer phenomenological equation of multi-potential fields is obtained.And on the basis of that,taking an oil pipeline as an example,the field influence factor of exergy transfer coefficient is calculated,thereby to providing theoretical basis for transportation mechanism of practical pipeline.