| Today low-carbon economy is becoming the trend of economic development. Natural gas was regard as one of the most important clean energies. CO2 is a kind of high level acidic gas in natural gas. CO2 can not only reduce the quality of natural gas, but also corrode metal pipes and equipments and cause potential safety hazard. It even causes the greenhouse effect and serious harm to human health. The national mandatory standards get a new standard for the CO2 concentration of natural gas in 2012. The CO2 concentration adjusted from less than or equal to 3%(1999) to less than or equal to 2%. The purification process of natural gas must achieve the deep decarburization.At present, alcohol amine method is one of the most common ways to remove carbon dioxide in natural gas industry. Compared with other alkanolamine, MDEA 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, as a kind of tertiary amine, can not react with CO2 directly. A small amount of catalytic and activated component can be added in the MDEA solution to promote CO2 removing from natural gas.The main intent of this paper is to study the CO2 adsorption capability of the activated MDEA solutions. Using N2 and CO2 simulates the natural gas which contains acidic components, the concentration of CO2 is 100g/m3. First of all, the effect of different activation components such as DEA, MEA and heterocyclic amine on the properties of MDEA is studied. Second, the reaction mechanism of MDEA absorption of CO2 promoted by activation agents is discussed and the best decarburization solvent is selected. Third, because H2S contained in the natural gas will affect the absorption CO2 of MDEA solution. The experiment also is to study the effect of H2S additions on the properties of activated MDEA solution absorption CO2. Then regeneration, foam and corrosion effect of this decarburization solvent is tested at last.From the dynamics experiments, the conclusions is drawing as follows, catalytic and activation effect is HZ> HA> DEA> MEA. Adding equal HZ MDEA solution has the longest break-through time and biggest break-through carbon capacity. Therefore, we take HZ as the best activator. Through studying how the additons of the HZ effects on the absorption of CO2 and H2S in the simulated gas with H2S, we found that the better CO2 absorption while the little better H2S absorption, as HZ addition quantity increasing. The regeneration temperature effect of activated MDEA solution is 115℃>125℃>105℃, and the best regeneration time is 30 min. However, regeneration times have no influents on MDEA solution performance of absorption acid gas. The acid fractions of natural gas, the corrosion product (FeS) will increase the foaming tendency of activated MDEA solution. Experiment from various defoaming agent selects a best one DF-112, that can well eliminate activated MDEA solution’s foaming, and the best dosage is 0.8 per thousand. The activated MDEA solution’s corrosiveness is that the rich solution is far greater than that of the lean. The addition of activator HZ has no effect on MDEA solution’s corrosion. Imidazoline inhibitor can effectively inhibit activated MDEA rich solution from corrosing the equipment and its suitable dosage is 5 per thousand. |
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