输气管道的管存量优化控制

Optimized control of line pack of gas pipeline

目前,国内外对输气管道管存量的控制尚未有统一的标准,普遍采用运行经验结合管道仿真的方法制订管存量控制原则,缺乏最大管存量、最小管存量和最优管存量的理论计算依据。为此,以中亚天然气管道AB线为研究对象,基于动态规划算法计算了管道的最大管存量、最小管存量和能耗最小管存量,并结合运行经验的管道仿真结果,建立了一套包含3个层级的输气管道管存量控制原则与方法。研究结果表明:①对应给定的管道流量,在考虑压气站内燃压机组工况点可行域限制及管道运行操作限值的前提下,应用动态规划法确定管道的最大、最小安全管存量;②基于运行调度经验,通过仿真确定管道正常运行条件下的管存量合理界限;③应用动态规划法确定自耗气量(或能耗量)最小的运行方案及其所对应的管存量,以此作为日常运行管存量的控制目标;④将该管存量优化方法应用于中亚天然气管道AB线,相同年度输气量下,2014年较2013年自耗气量降低38.38×10~4 m^3,全线离心压缩机平均效率提高0.21%,全线压气站出站压力介于9.50~9.65 MPa的占比提高6.6%。结论认为,该方法可将输气管道管存量控制在最大安全管存量范围以下、最小安全管存量以上,尽可能按照自耗气量最小对应控制管存量。

So far, there has been no unified criterion on the line pack control at home and abroad, and the line pack control principle is commonly formulated based on operation experience, combined with pipeline simulation. In addition, there is no theoretical calculation basis for maximum, minimum and optimum line packs. In this paper, the Trans-Asia Gas Pipeline AB was taken as the research object. Its maximum, minimum and optimum line packs were calculated by means of the dynamic programming algorithm. Then, a set of three-level line pack control principles and methods for gas pipelines were developed based on operation experience and pipeline simulation results. And the following research results were obtained. First, for a given pipeline throughput, the maximum and minimum safe line packs are determined using the dynamic programming method while the feasible operation ranges of gas turbine driven units in compressor stations and the limit values of pipeline operation are satisfied. Second, based on the operation dispatching experience, a reasonable interval of line pack for normal operation of a gas pipeline is determined by conducting simulation. Third, the operation scheme with the minimum self-consuming gas (or energy consumption) and its corresponding line pack are determined by using the dynamic programming method, and it is taken as the objective of line pack control during daily pipeline operation. Fourth, when this line pack optimization method is applied in the Trans-Asia Gas Pipeline AB, at the same pipeline throughput, the self-consuming gas is 383.8 thousand m^3 more, the average efficiency of centrifugal compressors is 0.21% higher, and percentage of outlet pressure of 9.50 9.65 MPa of compressor stations is 6.6% higher in 2014 than in 2013. It is concluded that by virtue of this method, the line pack can be controlled below the maximum safe line pack and above the minimum safe line pack, and it can be kept according to the minimum self-consuming gas as much as possible.