Studies of the unavoidable exergy loss rate and analysis of influence parameters for pipeline transportation process

Abstract

According to the exergy balance relationship among the various items in the crude oil transportation process system, the exergy balance equation is established and each exergy loss is calculated. In a sense, the essence of exergy analysis method relies on the calculation and the analysis of system exergy loss. The unavoidable exergy loss is defined based on the required minimum exergy loss from the technology standpoint during the pipeline conveying process. In order to truly reflect the degree of effective energy utilization, this article puts forward the unavoidable exergy loss rate as evaluation index, which is based on the exergy analysis criterion consisted by exergy loss coefficient and exergy loss rate. Taking an oil pipeline as an example, the changes of the unavoidable exergy loss are studied under different designed parameters. And the unavoidable thermal exergy loss is the dominant position. Change situations of the unavoidable exergy loss rate are explored. Through analysis, the trend and the regularity of the unavoidable total exergy loss rate are identical with the unavoidable thermal exergy loss rate. Then the orthogonal experiment method is used to compare the different influence degrees to the pipeline unavoidable exergy loss rate. The results are as follows: diameter, insulation thickness and buried depth, which can provide the reference for the energy-saving transportation of crude oil pipeline. Keywords: Unavoidable exergy loss, Exergy analysis criterion, Unavoidable exergy loss rate, Orthogonal experiment