Energy Reports (Nov 2021)
Analysis of natural gas flow reversal in integrated energy system based on dynamic simulation
Abstract
The inertial water hammer pressure propagates along the pipeline at the speed of sound wave, which makes the pressure along the pipeline rise or fall rapidly and the inertial water hammer pressure attenuate in the process of propagation. In the 50–60 km long pipeline, it will attenuate about 2/3-3/4. However, in the integrated energy system (IES), the length of natural gas pipeline is short, and the attenuation of water hammer pressure is small. The distance between the user end and the source end is short, so the user end will be affected by the water hammer pressure, including gas turbine, gas boiler and combined heat and power unit (CHP), which will result in its unstable operation, so it is necessary to analyze the impact of water hammer pressure in the IES. The rapid rise or fall of pressure along the pipeline caused by water hammer pressure will cause the reflux of natural gas, causing the instability of gas supply, and affect the safe operation of users. In order to solve this problem, this paper analyzes and calculates the dynamic fluctuation process of the natural gas system in the IES based on the method of characteristic which is suitable for the analysis of hyperbolic partial differential equation. In the process of modeling, the absolute value term of the simulated natural gas flow direction is retained,instead of thinking that the direction of flow is not change, and the difference method of the absolute value term is discussed and analyzed, and finally the calculation process is realized; After that, the simulation algorithm and program are used to analyze the problem of natural gas reflux caused by water hammer pressure in a specific comprehensive energy system, and the analysis and calculation are carried out to realize the real restoration of its operation state, which has important practical value.
