Effects of gasoline removal on heating value of natural gas

Abstract

A simulation study of likely uncertainties in molecular weight and heating value of the gas mixture as predicted from measured or calculated sonic speed. The sonic speed, molecular weight and heating value of natural gas were studied as a function of random fluctuation of the gas fractions. A method of sonic speed prediction was developed and used for over 50,000 computer-simulated variants of component concentrations in four- and five-component mixtures. Comparison of the obtained and the reference data on binary (methane–ethane) and multicomponent (Gulf Coast) gas mixtures under standard pressure and moderate temperatures indicates predictability of sonic speed on the basis of the binary virial coefficients, sonic speeds and heat capacities of the pure components. The results for two natural gas mixtures — with and without nonflammable components — are reported. Bivariate distribution and covariance elliptic zone plots are presented for three pairs of dependences of practical interest: molecular weight–sonic speed, heating value–sonic speed and heating value–molecular weight. The correlation coefficients, covariance, and regression equations are given for each pair of variance and mixture.