Numerical Approach for Steady State Analysis of Hydrogen–Natural Gas Mixtures Flows in Looped Network

Abstract

This paper presents a mathematical formulation for analyzing the steady state behavior of a binary mixture of hydrogen–natural gas in pipelines networks. Throughout the paper, natural gas flow is assumed to be pure methane (CH4) flow as the latter is the main component of natural gas. The model development is based on a new correlation for compressibility factor of gas mixture. The built correlation is reposed on the resolution of Soave–Redlich–Kwong (SRK) Equation Of State (EOS). The compressibility factor, numerical solution of real gas EOS, is validated through a comparison with experimental values issued from gas compressibility charts as well as empirical results inspired by analytical expressions. Basing on the established expression for the compressibility factor, continuity and motions equations are integrated in steady state. Thus, a pressure drop expression is given. The latter is used to balance a looped network of hydrogen–natural gas mixture. The implemented algorithm of looped network balancing is reposed on resolution of nodes and loops equations using Newton–Raphson method. Pressure and velocity evolutions along the network ducts are followed up, and thus, the effect of hydrogen injection in natural gas network is analyzed.