Objective The object of natural gas energy measurement is the total heat quantity generated after complete combustion. The energy value of natural gas is usually determined by multiplying the measured value of volume by the volume calorific value, and the volume calorific value depends on the composition of natural gas, that is, the mole fraction of each component in natural gas. The composition of natural gas in multi-gas source pipeline network usually changes with space position and time, thus each metering station of the pipeline network needs to determine the volume calorific value of natural gas input or output from the station at different times. Class A metering stations of long-distance pipelines in China are equipped with on-line gas chromatograph to analysis the calorific value of natural gas, while class B and class C metering stations can use simulation method to assign value to the calorific value of natural gas, so as to reduce the investment, operation and maintenance cost of configuring gas chromatograph.

Methods Based on the theoretical basis of pipeline network simulation for energy measurement, aiming at a multi-gas source annular pipeline network, this paper establishes the operation simulation model with the functions of natural gas component tracking and calorific value calculation by using TGNET and SPS simulation software. In order to improve the accuracy of simulation results, the gas transmission efficiency of pipe section, a key parameter in the simulation model, is calibrated based on historical operation data.

Results TGNET and SPS models are respectively used to dynamically simulate the historical operation process of the pipeline network for 48 hours. The deviation between the calorific value simulation result of TGNET model and the historical value is within 0.3%.

Conclusions The energy measurement of multi-gas source annular pipeline network based on operation simulation is a feasible method. The research results provide an operable method for the implementation and popularization of natural gas energy measurement in China.