Looped Pipeline System for Increasing the Capacity of Natural Gas Transmission

At present, gas engineers use the simple Campbell s equation to determine the proper length of para llel gas pipelines. The Campbell s equation was proposed for horizontal pipelines with the assumption that the gas compressibility factor and temperature throughout the pipeline are constant. Therefore, the Campbell s equation has a notable error for an inclined pip eline. In this pap er, the Campbell s equation was extended in away that it can be used fo r inclined pipelines. In order to make a comparison between the extended and original equations, a pipeline with different slopes was used. The results show that in the case of using a pipeline with more than 2 degrees in slope , the resultant error is increased to II percent by using the original Campbell s equation. For validation of the extended Campbell s equation, the results of this equation are compared to the results of HYSYS software (version 3.1) in which the temperature and gas compressibility fa ctor are not considered constant. The results indicate that the average error of the extended equation is less than 2 percent.