Abstract:

China’s natural gas demand is substantial, accompanied by a high degree of external dependence. Hydrogen, as an alternative fuel, can be transported over long distances through blending into existing gas pipelines, while simultaneously optimizing the national energy supply structure. This study employs TGNET software to conduct steady-state simulations and analyses. The results indicate that for long-distance gas transmission pipelines, when the relative terrain elevation difference (△h) exceeds 200 m, the influence of terrain elevation differences on pipeline pressure loss cannot be neglected. Conversely, in the case of pure hydrogen pipelines (simulated under extreme conditions), due to the low density of hydrogen, the smaller the relative density of the gas at a constant volumetric flow rate, the higher the outlet pressure and the lower the pressure loss. Thus, the impact of elevation differences on pressure loss in gas pipelines is negligible. Based on domestic and international experience regarding optimal hydrogen blending ratios, simulations were conducted with a 15% hydrogen blending ratio. Under identical operating conditions, blending 15% hydrogen into long-distance natural gas pipelines can reduce the pressure loss by 0.1–0.36 MPa, while simultaneously lowering the carbon emission intensity associated with natural gas utilization.

Key words: TGNET, gas pipeline, hydrogen blending into natural gas