The Study On Carbon Dioxide Absorption From Natural Gas In Catalytic And Activated N-methyldiethanolamine Solution

Low-Carbon Economy is the trend of economic development today. Natural gas has become one of the most important clean energies. CO2is a kind of high levels acidic gas in natural gas. CO2can not only reduce the quality of natural gas, but also corrode metal pipes and equipments and cause potential safety hazard. Sometimes CO2could even threat human health and lead to environment pollution. Therefore, CO2must be removed from natural gas before transportation and utilizing.Alkanolamine technology is one of the most common ways to remove carbon dioxide. Compared with other alkanolamine, MDEA (methyldiethanolamine) is more popular because of some excellent characteristics such as high adsorption capability, high chemical stability, low corrosion, low regeneration heat and hard to foam and degradation. MDEA is a good choice to be the main component of a solution, a small amount of catalytic and activated component can be added in the solution to promote CO2removing from natural gas.The intent of this paper is to study the CO2adsorption capability of the catalytic and activated MDEA solutions. Using N2and CO2simulates the natural gas which contain acidic components, the concentration of CO2is100g/m. First, the effect of MDEA concentration, reaction temperature and the gas liner velocity on CO2absorption reaction is studied under static conditions. Second, the effect of different activation components such as DEA, MEA and heterocyclic amine on the properties of MDEA is studied. Third, the reaction mechanism of MDEA absorption of CO2promoted by activation agents is discussed and the best decarburization solvent is selected. Then the CO2removal effect and the stability of the best solvent is checked under dynamic and continuous condition. The corrosion effect of this decarburization solvent is tested at last.The effect of MDEA concentration, reaction temperature and the gas liner velocity on CO2absorption reaction under static condition is studied. The results show that with the increasing of MDEA concentration, absorption efficiency first increased and then decreased. In the first60minutes, the absorption efficiency of35%MDEA solution is the best, when the reaction time is more than60minutes,45%MDEA solution becomes the best decarburizer. With the increasing of reaction temperature, the effect of absorption increases at first and then decreases and40℃is the optimum reaction temperature, Smaller gas liner velocity is better than larger gas liner velocity. In follow-up studies, the concentration of MDEA is45%, the reaction temperature is40℃and the gas velocity is0.52m/min.From the dynamics experiments, the conclusions can draw as follows, catalytic and activation effect is HA>MEA>DEA, the MDEA solvent that being activated by5%HA can be the best decarburization. The time of break-through and break-through carbon capacity of the best activated MDEA is7.75times longer and8.31times larger than non-activated MDEA. The dynamics experiments proved that the best decarburizer has high stability and large decarburization rate. The corrosion experiments show that higher temperature leads to higher corrosion rate. The regeneration solvent has higher corrosion than fresh solvent. The solution of MDEA added HA is no more corrosive than MDEA solution, HA cannot aggravate corrosion of MDEA solution.