Abstract

Hydrogen blending of natural gas is an effective way to achieve carbon neutrality. In order to evaluate the influence of different static mixers on the mixing performance of natural gas and hydrogen, numerical simulation methods were used to analyze in detail the effects of SMX type static mixers, LPD type static mixers and KSM type static mixers on the mixing uniformity, internal flow field structure and pressure loss of natural gas and hydrogen. The results show that in terms of blending uniformity, SMX static mixer>LPD static mixer>KSM static mixer. Based on flow characteristics, the spiral plate of the KSM static mixer reduces the time and opportunity for air flow to contact with each other, the two elliptical plates of the LPD static mixer promote the mixing of the mixed gas to generate eddy current and the SMX static mixer can realize the mixing in two dimensions: Flow direction and radial direction. For pressure loss, the pressure loss of the three static mixers increased with the increase of the number of mixing units and basically showed a linear increase and the pressure loss of the LPD static mixer was about twice that of the SMX static mixer and the KSM static mixer.

Keywords: Static mixer; Hydrogen natural gas blending; Hydrogen mixing element; Mixing uniformity; Flow characteristic

Nomenclature: A: Cross-sectional area of the pipeline; c: Volume fraction of each sampling point; : Volume average concentration at the static mixer outlet; D1: Inlet pipe diameters of natural gas, mm; D2: Inlet pipe diameters of hydrogen, mm; ΔP: Pressure loss; σ: Standard deviation; ζ: Concentration mixing influence factor