多气源天然气输配管网的能量计量方法

随着我国多气源供应格局的形成,天然气计量方式逐渐从现行的体积计量方式向能量计量方式转变。现行的《天然气能量的测定》标准对多气源输配管网系统没有给出具体可操作的能量计量程序,若采用热值数量加权平均赋值方法,能量计量误差可达8%,不能满足能量计量标准GB/T 18603—2014《天然气计量系统技术要求》对能量计量精度的要求。为此,根据天然气输配管网的拓扑结构和气量平衡原理,利用天然气输配管网中现有的流量计量仪表对多气源输配管网进行状态重构,提出了一种区域多气源天然气输配系统状态重构能量计量方法,并对管网状态重构后进行能量计量的误差进行了分析。结果表明:(1)所提出的方法确定了多气源输配管网状态重构所需流量仪表的最少数量及仪表布置方法 ;(2)多气源输配系统管网状态重构后,各下游天然气用户能量计量的误差均不超过0.5%,可满足GB/T 18603—2014对能量计量准确度最高等级(A级)误差在1%以内的要求。该研究成果为我国天然气能量计量技术的应用和推广提供了一种可操作的程序。

An energy measurement method for multi-source natural gas distribution pipeline networks

As the multi-source gas supply pattern is formed in China, the natural gas measurement mode is gradually transformed from the current volume measurement to the energy measurement. There is no specific energy measurement program for a multi-source distribution pipeline system in the current standard Energy Determination for Natural Gas. If the thermal-value weighted average assignment method is adopted, the energy measurement error is up to 8%, so it cannot meet the requirements of energy measurement accuracy stipulated in the Technical Requirement of Measuring Systems for Natural Gas (GB/T 18603-2014). According to the topological structure and gas balance principle of natural gas distribution pipeline networks, the state reconstruction of multi-source distribution pipeline networks was carried out by using the existing flow metering instruments in the natural gas distribution pipeline networks, and an energy measurement method of multi-source regional natural gas distribution pipeline system based on state reconstruction was established. The energy measurement error after the state reconstruction of pipeline network was analyzed. It is indicated that by virtue of this method, the minimum number of flow meters required for state reconstruction of multi-source distribution pipeline network and the piping method are determined. Furthermore, the energy measurement error of the downstream users after the state reconstruction of multi-source distribution pipeline network is less than 0.5%, which meets the minimum error requirement (Class A) of energy measurement accuracy, i.e., ≤1%. The research results provide an operational procedure for the application and popularization of domestic natural gas energy measurement technologies.