Has anyone used HYSYS to simulate molecular sieves for CO2 removal using the MDEA method?
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I have a question for everyone: can the removal of CO2 using the MDEA method be simulated with HYSYS? MDEA (N-Methyldiethanolamine), also known as N-methyldiethanolamine, has the molecular formula CH3-N(CH2CH2OH)2. Its molecular weight is 119.2, boiling point is 246–248°C, flash point is 260°C, freezing point is -21°C, and the latent heat of vaporization is 519.16 KJ/kg. It is miscible with water and alcohols, and slightly soluble in ethers. Under certain conditions, it has a strong absorption capacity for acidic gases such as carbon dioxide; it also has low reaction heat, a low desorption temperature, stable chemical properties, and is non-toxic and non-degradable. Pure MDEA solution does not react with CO2, but its aqueous solution can react with CO2 according to the following equations: CO2 + H2O == H+ + HCO3- (1) H+ + R2NCH3 == R2NCH3H+ (2) Equation (1) is governed by the liquid film effect, resulting in a very slow reaction rate; whereas equation (2) is an instantaneously reversible reaction. Therefore, equation (1) represents the key step in the absorption of CO2 by MDEA. To increase the absorption rate, 1–5% of the activator DEA (R2/NH) is added to the MDEA solution, and the reaction proceeds as follows: R2/NH + CO2 == R2/NCOOH (3) R2/NCOOH + R2NCH3 + H2O == R2/NH + R2CH3NH+HCO3- (4) (3) + (4): R2NCH3 + CO2 + H2O == R2CH3NH+HCO3- (5) As can be seen from equations (3) to (5), the activator absorbs CO2 and transfers it to the liquid phase, thereby accelerating the reaction rate while also regenerating MDEA. The MDEA molecule contains a tertiary amine group; upon absorbing CO2, it forms bicarbonate, and far less heat is required for its regeneration by heating compared to that needed for the carbamates formed by primary and secondary amines. Regarding this related principle, I would like to know how much CO2 can be absorbed at a certain temperature and pressure for a given amount. How can this be simulated? This post was last edited by HaiChuanDeFeng on 2008-6-16 22:57.]
I have simulated this absorption using ASPEN; the amount of CO2 that can be absorbed depends on your target value (i.e., how much CO2 you want to recover), and as for the amount of MDEA required, you need to consult relevant solubility tables. Simulation is divided into absorption and desorption; absorption occurs under pressure, while desorption takes place at atmospheric pressure.
I have also used ASPEN to simulate this absorption process, but it fails to converge. Did you use the ELECNRTL or KEMEA thermodynamic model?
I want to use KEMEA for simulation; I’m not sure if it’s a good option. I don’t know how to write the reaction equations, and I also don’t know how to write ionic equations in HYSYS Could someone with experience give some advice?
I’m using a professional Amine amine pack model
In the near future, ion equations will be available in Hysys
Find the client who specified the use of HYSYS to obtain the amine package; or finding one that uses pirated versions will also work, and then the electrolytes can be processed. However, it is not recommended to use Hysys for handling electrolytes, as it is not Hysys’s strong point.
To handle electrolytes in HYSYS, an external electrolyte package is required. I have used HYSYS to simulate the absorption of CO2 by amines, utilizing the amine package available within the software
I’m dizzy from looking at it; it’s all so confusing, and it seems like no one has given a direct answer
Currently, amine envelopes are used for static simulation, and dynamic simulation is then carried out based on that static simulation.