复杂天然气管网周转量计算模型及其应用——以川渝天然气管网为例

管网周转量测算是控制管道运行现金成本、管道能源消耗，实现降本增效的措施之一。川渝天然气管网作为目前国内最复杂的区域性管网（由枝状管网和环形管网交错结合在一起），具有进出气点多、管线压力等级复杂、管网输配调度灵活、调峰方式多样等特点，同时存在天然气气体流向复杂、原始数据采集不实时、计算周期难确定等问题。为此，根据该复杂天然气管网特点，建立了枝状管网和环状管网管线图模型，采用“微元法”原理和方法，建立了较为适合复杂天然气管网特点的周转量计算模型，将整个管网系统按照管理层级层层分解，将周转量的测算细分到每一管段，以作业区作为一个计算区间进行测算，再进行层层累加求和，即得到整个系统的周转量。通过对比实例计算，得出了用“微元法”计算复杂天然气管网周转量的方法较为符合川渝管网的实际的结论。该成果可为全国联网天然气管道周转量的测算提供借鉴，有助于联网管道的销售管理、结算管理和运行管理。鉴于复杂天然气管网的特殊性，可采用年度或季度平均法，在统计分析的基础上计算周转量。

A calculation model of the turnover volume in a complex natural gas pipeline network:A case study of the Shichuan and Chongqing Gas Pipeline Network

The calculation of the turnover volume in a line network is one of the effective means to control the input operation cost, reduce the energy consumption, and achieve the goal of cost decreasing and efficiency increasing. Branch lines and ring lines are cross connected each other in the most complicated pipeline network covering the areas in Sichuan and Chongqing. This not only leads to unique features such as numerous inlet/outlet points, complex grades of line pressures, a flexible distribution dispatching system, various peak shaving methods, etc., but brings about many bottlenecking problems like the gas current direction getting quite complicated, the original data not being collected in real time, the calculation cycle being hard to determine, and so forth. In view of this, two physical models were first established: the branch line model and the ring line model. Then, the infinitesimal diving modeling method was applied to establish a turnover volume calculation model more adaptable for a complex pipeline network. Thus, the whole network system was discomposed in hierarchical levels; the turnover volume was calculated on each line section with an operation zone as a computation interval. Finally, the cumulative sum of the calculated results section by section was obtained as the total turnover volume of the whole line network system. A few calculation examples demonstrated that the above method is quite practical and feasible for the complex pipeline network covering the areas in Sichuan and Chongqing. This study provides reference for the estimation of the turnover volume of national pipeline network and is of guidance to the sales, settlement, and operation management of pipes connected to the internet. In the end, due to the particularity of such a complex gas pipeline network, the annual or seasonal average method was recommended to use for the calculation of the turnover volume based on the statistical analysis.