Investgation On The Mass Transfer Of Alcoholamine Solution Absorbing CO₂ And The Purification Of Absorbent

Due to the degradation of the organic amine solution in the process of capturing post-combustion CO₂,it leads to the loss of absorbent,the decrease of cyclic absorption and desorption performance and the high energy consumption,which hinders the further development,promotion and application of this technology.This work intends to explore solutions from two different perspectives:absorbents and degradation products.On the one hand,select absorbents with good anti-degradation performance,strengthen their CO₂ absorption process,and establish an improved mass transfer model for universal packed colums.On the other hand,the effect of degradation products on the absorption and desorption performance of amine solutions was studied,and a method for quickly evaluating the performance of degradation products was established.It can effectively screen out degradation products that have side effects on the absorption performance of organic amines and guide their removal.The precise removal technology of degradation products provides theoretical support.The main research contents and innovative results are as follows:(1)Through the N₂O physical solubility experiment and the"N₂O analogy method",the physical solubility of CO₂ in the amine solution is indirectly obtained.The concept and model of physical solubility are introduced for the first time,and theK_Ga_vmodel of total volume mass transfer coefficient and the CO₂ outlet concentrationy_CO2,outmodel are preliminarily improved.(2)The CO₂ equilibrium solubility model was measured and established by the CO₂equilibrium solubility device.The concept and model of chemical equilibrium solubility are introduced for the first time to further improve theK_Ga_vmodel and they_CO2,outmodel.(3)The concept and model of effective phase interface area are introduced for the first time to further improve theK_Ga_vmodel.By establishing the mass transfer coefficientK_Gmodel and the effective phase interface area a_v model respectively,the limitations of the application of the packed colum mass transfer model are broken,and the application of the mass transfer model is enhanced.(4)For the first time,it is proposed that the purification and removal of amine solution degradation products need to be targeted.A method for quickly evaluating the effects of degradation products on the absorption and desorption performance of absorbents was established,and degradation products with side effects on absorbents were screened out,providing a basis for the development of precise removal of degradation products.(5)The influence of the chemical structure and chain length of the heat-stable salt(HSS)on the absorption and desorption performance of monoethanolamine(MEA)solution was studied.The rapid detection method of HSS content in MEA was studied,and a method for detecting the concentration of individual substances and HSS in MEA solution based on an automatic potentiometric titrator was established.The adsorption and separation methods of HSS by solid adsorbents such as activated carbon,sepiolite and quartz were explored.