The formation of gas hydrates and the effect of inhibitiors on their formation process
Natural gas hydrate is a solid crystalline compound produced by combining water and gas and it is considered as the clathrates. Guest gas molecules are stuck insider the pores of water networks produced by hydrogen bonds between molecules of water. There are different ways to analyze the hydrate formation operating conditions (temperature and pressure) including drawing the logarithm of pressure changes curve in terms of gas temperature which is one of the most common methods. In this case, the curve is straight line that is easy to analyze. The structure of hydrates in water-gas area is kept by molecules of the solution in aqueous phase area. As a result, H2S and CO2 accelerate the formation hydrates at high temperatures because they are more soluble in water than most hydrocarbons. The pressure leads to the formation of the network. In the case of pentane and larger molecules, pressure breaks the network and prevents the formation of stable hydrates.
Keywords: hydrates, hydrogen bonding, free water, methane, carbon dioxide