Design Appproach Accounts for Condensate in Gas Pipelines

Abstract

With more than 1.2 million miles of gas pipelines crisscrossing the entire landmass of the United States, there is little doubt that the capital investment on these pipelines is tremendous. Optimal use of these pipelines is a must, both for operational reasons and cost-effectiveness. One of the prevalent problems in these pipelines is condensation. The existence of the condensate, in addition to reducing deliverability, creates several operational problems. Pigging and drips are two of the methods used to alleviate this problem. Since condensates are not uniformly distributed along the pipeline, either of these two solution strategies will be rendered ineffective unless the distribution of condensate in the pipeline is known. During the past several years, a compositional hydrodynamic model has been developed at Penn State University. This couples a phase behavior model with a fundamental multiphase hydrodynamic model. This model has since been tested and validated. Several design strategies and operational options that may be encountered in the field are defined and modelled. The results of these are reported in this paper. The results clearly demonstrate that in spite of the complex nature of this problem, condensation in pipelines can be modelled by using the approach presented here.

Gas-Liquid Stratified Flow in Pipeline with Phase Change

“…There exist several problems in the pipeline network system that the saturated vapor in gas would condense due to pressure and temperature drop [7,8]. The condensate would attach to the pipe wall as a form of film or droplet [9,10].…”

“…The energy transfer model has been taken into the flow progress for the optimization of transportation, estimation of corrosion, or prediction of wax deposition [31,32]. Concretely, the two-dimensional (2D) momentum and three-dimensional (3D) energy equations for both phases have been established for dynamic and thermal numerical simulation [8,27,30,33]. The smooth or wavy interface between phases was obtained in a different range of flow rates [17].…”