It is necessary to understand all the prerequisites, which result in gas hydrate formation for safe design and control of a variety of processes in petroleum industry. Thermodynamic hydrate inhibitors (THIs) are norma...It is necessary to understand all the prerequisites, which result in gas hydrate formation for safe design and control of a variety of processes in petroleum industry. Thermodynamic hydrate inhibitors (THIs) are normally used to preclude gas hydrate formation by shifting hydrate stability region to lower temperatures and higher pressures. Sometimes, it is difficult to avoid hydrate formation and hydrates will form anyway. In this situation, kinetic hydrate inhibitors (KHIs) can be used to postpone formation of gas hydrates by retarding hydrate nucleation and growth rate. In this study, two kinetic parameters including natural gas hydrate formation induction time and the rate of gas consumption were experimentally investigated in the presence of monoethylene glycol (MEG), L-tyrosine, and polyvinylpyrrolidone (PVP) at various concentrations in aqueous solutions. Since hydrate formation is a stochastic phenomenon, the repeatability of each kinetic parameter was evaluated several times and the average values for the hydrate formation induction times and the rates of gas consumption are reported. The results indicate that from the view point of hydrate formation induction time, 2 wt% PVP and 20 wt% MEG aqueous solutions have the highest values and are the best choices. It is also interpreted from the results that from the view point of the rate of gas consumption, 20 wt% MEG aqueous solution yields the lowest value and is the best choice. Finally, it is concluded that the combination of PVP and MEG in an aqueous solution has a simultaneous synergistic impact on natural gas hydrate formation induction time and the rate of gas consumption. Furthermore, a semi-empirical model based on chemical kinetic theory is applied to evaluate the hydrate formation induction time data. A good agreement between the experimental and calculated hydrate formation induction time data is observed.展开更多
Carbon dioxide(CO_(2))is an influential greenhouse gas that has a significant impact on global warming partly.Nowadays,many techniques are available to control and remove CO_(2) in different chemical processes.Since t...Carbon dioxide(CO_(2))is an influential greenhouse gas that has a significant impact on global warming partly.Nowadays,many techniques are available to control and remove CO_(2) in different chemical processes.Since the spray dryer has high removal efficiency rate,a laboratory-scale spray dryer is used to absorb carbon dioxide from air in aqueous solution of NaOH.In the present study,the impact of NaOH concentration,operating temperature and nozzle diameter on removal efficiency of CO_(2) is explored through experimental study.Moreover,the reaction kinetic of NaOH with CO_(2) is studied over the temperature range of 50-100℃ in a laboratory-scale spray dryer absorber.In the present contribution,a simple reaction rate equation is proposed that shows the lowest deviation from the experimental data with error less than 2%.展开更多
文摘It is necessary to understand all the prerequisites, which result in gas hydrate formation for safe design and control of a variety of processes in petroleum industry. Thermodynamic hydrate inhibitors (THIs) are normally used to preclude gas hydrate formation by shifting hydrate stability region to lower temperatures and higher pressures. Sometimes, it is difficult to avoid hydrate formation and hydrates will form anyway. In this situation, kinetic hydrate inhibitors (KHIs) can be used to postpone formation of gas hydrates by retarding hydrate nucleation and growth rate. In this study, two kinetic parameters including natural gas hydrate formation induction time and the rate of gas consumption were experimentally investigated in the presence of monoethylene glycol (MEG), L-tyrosine, and polyvinylpyrrolidone (PVP) at various concentrations in aqueous solutions. Since hydrate formation is a stochastic phenomenon, the repeatability of each kinetic parameter was evaluated several times and the average values for the hydrate formation induction times and the rates of gas consumption are reported. The results indicate that from the view point of hydrate formation induction time, 2 wt% PVP and 20 wt% MEG aqueous solutions have the highest values and are the best choices. It is also interpreted from the results that from the view point of the rate of gas consumption, 20 wt% MEG aqueous solution yields the lowest value and is the best choice. Finally, it is concluded that the combination of PVP and MEG in an aqueous solution has a simultaneous synergistic impact on natural gas hydrate formation induction time and the rate of gas consumption. Furthermore, a semi-empirical model based on chemical kinetic theory is applied to evaluate the hydrate formation induction time data. A good agreement between the experimental and calculated hydrate formation induction time data is observed.
文摘Carbon dioxide(CO_(2))is an influential greenhouse gas that has a significant impact on global warming partly.Nowadays,many techniques are available to control and remove CO_(2) in different chemical processes.Since the spray dryer has high removal efficiency rate,a laboratory-scale spray dryer is used to absorb carbon dioxide from air in aqueous solution of NaOH.In the present study,the impact of NaOH concentration,operating temperature and nozzle diameter on removal efficiency of CO_(2) is explored through experimental study.Moreover,the reaction kinetic of NaOH with CO_(2) is studied over the temperature range of 50-100℃ in a laboratory-scale spray dryer absorber.In the present contribution,a simple reaction rate equation is proposed that shows the lowest deviation from the experimental data with error less than 2%.
