چكيده به لاتين
Abstract:
Natural gas extremely used in the world. Gas hydrate considered as a problem when it was discovered that they were clogging gas pipelines. Recently, natural gas hydrates have attracted atemtion as a source of energy. It is generally assumed that hydrates in ocean contain a huge volume of natural gas. The most widely cited estimate of global hydrate-bound gas is 21×1015 m3 at STP conditions. This huge gas hydrate reservoir is further suggested as an important component of the global carbon cycle and as a future energy source. 15% of the gas traped in hydrates can supply energy of required in world for 200 years. Understanding of equilibrium condition of formation and decomposition of gas hydrate is important to provide an energy supply assurance for the world. Clathrate hydrate also can be used as a source of saving greenhouse gases, especially carbon dioxide, release into the atmosphere.
Recently, support vector machine technique has been used as a method of modeling in engineering complex systems.
In this work, hydrate phase equilibria for the binaries systems such as methane+water/ice, ethane+water/ice, propane+water and carbon dioxide+water in porous media were predicted. Predictions of the SVM models having acceptable agreement with available experimental data prove the reliability of the SVM tool for estimation of hydrate phase equilibrium in porous media. Moreover, application of SVM technique in estimation of equilibrium pressure is examined and results are compared to other existing thermodynamic models proving superiority of the SVM models over conventional thermodynamic ones.
In this model, the formation of methane, ethane and propane hydrates equilibrium pressure is used as output and hydrate formation temperature is used as input. Here, 183 equilibrium data of gas hydrate is used. The Genetic Algorithm (GA) is applied to obtain the optimal parameters of the model. The final results indicate the reliability of the proposed models that the absolute average deviations percentage (%AAD) of methane, ethane, propane and carbon dioxide respectively are 0.37, 1.72, 0.57 & 2.47.
Keywords: Gas hydrate, Phase equilibria, Porous Media, Support Vector Machine, Reliable models, Modeling.
