The use of natural gas becomes more attractive due to its efficiency and cleaner combustion product and also as the oil price remains high, natural gas has been a potential energy source to displace it. However, according to U.S. EPA report on Global Anthropogenic Emission o f Greenhouse Gases non-CO2 2006, the methane emission from natural gas system accounts for 24% of the total methane emission to the atmosphere, and are produced from vented, fugitive leaks of the gas or accidental release of gas or liquid natural gas. Controlling methane gas emission is crucial not only it will reduce the economic loss, but also it reduces the greenhouse gas emission to the atmosphere. In addition, methane gas mixture is flammable in the range of 5% -15% of methane in the methane-air mixture and thus reducing the methane gas emission implied less hazardous material being released to the environment.

In this research the amount of methane emission will be estimated using vapor dispersion model and conservation of mass, energy and momentum will be established to predict the correlation of the downwind temperature and concentration of the dispersed methane gas. For natural gas system, Gaussian dispersion approach will be used to estimate the concentration and further will be modified based on the true parameters measured such as wind profile, humidity and solar radiation in the field test. The dense gas dispersion model will be used to estimate the emission from liquid natural gas release. Simulation of dense gas model using three-dimensional computational fluid dynamic (CFD) model will be presented.