جداسازي CO2 از مخلوط گازي CH4/CO2 به وسيله روش تشكيل هيدرات گازي در حضور نانوذرات اكسيد آهن به¬منظور ذخيره¬سازي دي¬اكسيدكربن و كاهش آلايندگي

Greenhouse gases after water vapor are mainly composed of carbon dioxide (CO2) an‎d methane (CH4). Since the presence of carbon dioxide along with methane in natural gas from biogas (CH4 + CO2) reduces its calorific value, the removal of carbon dioxide from this gas mixture is of particular importance. In addition, the storage an‎d reuse of removed carbon dioxide in various industries is important in two aspects: first, from the perspective of the environment an‎d the reduction of pollution, an‎d second, from the perspective of the optimal use of methane as a fuel with a higher calorific value. In this project, the separation of gas from the mixture by the formation of gas hydrate has been considered. Also, due to the fact that the molecules of carbon dioxide an‎d methane are about the same size an‎d their equilibrium conditions are close to each other, both molecules have an almost equal chance of being in hydrate cages an‎d as a result their separation coefficient is low. Therefore, increasing the separation efficiency as well as the selec‎tivity of the process is one of the issues being studied in the research. The main purpose of this project is to investigate the effect of adding nanoparticles to the aqueous phase as well as other parameters such as initial pressure (initial driving force), gas to liquid ratio an‎d nanoparticle concentration on gas consumption (" ∆" n_h), separation coefficient (S.F) an‎d recovery factor (R%) Carbon dioxide in the process of separation of gas from the gas mixture an‎d subsequently the degree of separation. Also, the other purpose of this study is to achieve better understan‎ding an‎d insight in improving the process of gas separation by forming hydrate to remove carbon dioxide from the gas mixture. Gas from the gas mixture (including 70% mol of CH4 an‎d 30% mol of CO2), was examined by laboratory by examining the formation of gas hydrate in the presence of iron oxide an‎d sodium dodecyl sulfate nanoparticles an‎d the synergistic effect of the two. In order to achieve this goal, all experiments were performed at 1 an‎d 4 degrees Celsius an‎d pressures of 40 an‎d 54 bar, an‎d it was found that the presence of nanoparticles at a suitable concentration range was determined. It has a positive an‎d significant effect on gas consumption as well as increasing the separation coefficient an‎d recovery factor in all systems. Among these, the best results were related to nanofluids with a concentration of 0.5% by weight an‎d also the synergistic effect of iron oxide an‎d sodium dodecyl sulfate nanoparticles, which significantly improved the separation coefficient an‎d recovery factor compared to pure water. For the gas consumption, which was eva‎luated at two pressures of 40 an‎d 54 bar, sodium dodecyl sulfate at a concentration of 0.01 wt at a pressure of 54 bar an‎d iron oxide nanoparticles at a concentration of 0.1 wt had the best performance. According to the results of the experiments, the optimal concentration for all systems including iron oxide nanoparticles an‎d sodium dodecyl sulfate was 0.5 an‎d 0.05% by weight, respectively, the best results were obtained in these conditions. It was also found that with increasing the ratio of gas to liquid an‎d force, the amount of gas consumption increases (according to the results, the maximum amount of gas consumption is related to the concentration of 0.01% by weight of sodium dodecyl sulfate (SDS) at a pressure of 54 bar, so that the amount of gas consumption in these conditions is about. 54.2% more than the pure water state) an‎d the recovery factor decreases but the separation coefficient has an optimal value at a given interval. On the other han‎d, it was observed that the amount of gas consumption is directly related to the initial pressure, while the separation coefficient an‎d recovery factor are inversely related to the initial pressure.

محمدرضا احساني , زهرا طاهري ريزي

محبوبه محمدطاهري

محسن نصراصفهاني , محسن محمدي