Energy use description and energy consumption evaluation in the transportation process of waxy crude oil pipeline

One of the essential parts for the energy efficiency management of crude oil pipelines is to describe accurately the energy use process of pipeline transportation and construct scientifically its energy consumption evaluation index system. At present, the calculation and statistical analysis of energy use, the process scheme optimization and energy consumption evaluation of crude oil pipeline are generally concentrated on the energy supply stations instead of the pipe itself which consumes the energy. Besides, effective energy consumption and ineffective energy consumption are treated without any distinction and energy consumption and energy loss are taken completely equal. Therefore, it is not beneficial for the further study on energy saving of pipeline systems. In this paper, exergy transfer was applied to energy use description and energy consumption evaluation in the process of pipeline transportation. It emphasizes the real value of energy and focuses on analyzing the mechanism of effective exergy consumption of the pipe itself. And it is a beneficial supplement and extension to the traditional energy consumption evaluation index system. It is indicated that among the total exergy consumption in the process of pipeline transportation, effective exergy consumption accounts for over 85%, among which the effective thermal exergy consumption is much higher than the effective pressure exergy consumption, so the energy saving of crude oil pipeline transportation shall focus on the way to reduce thermal energy consumption. The research results provide the theoretical basis and technical support for the safe and economic operation of crude oil pipelines.