Absorption And Performance Study Of CO₂ By Different Orangic Amine Adsorbents

The environmental problems caused by the intensification of greenhouse effect have attracted the attention of many countries.More and more CO2 absorbents have been studied.Chemical absorption method has been developed well and applied to industrial decarbonization technology.But it still has high energy consumption and high corrosion to be solved.In recent years,in order to reduce energy consumption,mixed amine adsorbents and solid materials absorbents loaded with amine have been proposed.In this paper,the absorption of different amines were determined.The best amine absorbent diethylenetriamine(DETA)was screened out.The absorption conditions of DETA were studied and the optimum absorption conditions were found out.The desorption of different amines were determined,the best amine desorption was screened out.Then,DETA with good absorption effect as the main method,the mixed amine liquid adsorbent and solid material adsorbent were prepared by two different methods.The mixed amine adsorbents is mainly composed of the amine DETA with the best absorption effect and N-methyldiethanolamine(MDEA)with the good desorption effect.Through the study of adsorption and desorption properties,the mixed amines with good absorption and desorption effects were screened out.The conditions of desorption and regeneration were also studied.The DETA with better absorption effect was loaded into solid material by different methods to synthesize solid adsorbents,and its structure was characterized and its absorption effect was studied.In the same absorption conditions,the absorption properties of seven different amines were determined and the absorbent with the best absorption effect was screened out.The results showed that the absorption rate and absorption amount of DETA were significantly higher than those of the other six amines,such as triethylene tetramine(TETA)and Tetraethylenepentylamine(TEPA),etc.Then the effects of temperature and concentration on absorption were studied.It was found that the absorption rate of CO2 increased with the temperature at different temperatures.However,the higher the temperature is,the process of absorption will be accompanied by a certain amount of desorption.Eventually lead to a reduction in the amount of absorption.The amount of CO2 absorbed by DETA at different concentrations increases with the concentration.However,high concentration absorbent with the increase of absorption amount of CO2,the viscosity increases and the diffusion effect weakens,which leads to the decrease of absorption.So the optimum absorption condition is the temperature of 298K and the concentration of 15%.Then the desorption properties of seven different amines were determined.It was found that MDEA had the best desorption effect.On the basis of previous studies,the DETA with better absorption effect was the main one,add to MDEA in different proportion to confect mixed amines for absorption and desorption.It was found that the higher the content of DETA,the better the absorbency,and the higher the content of MDEA,the better the desorption efficiency.Comprehensive consideration of absorption and desorption performance,mixed amines with DETA:MDEA=7:3 ratio,although the absorptivity of mixed amines is lower than DETA,the desorption rate can reach 93.54%,which improves the poor desorption effect of DETA.Compared with-TEPA and MEA,the absorptivity and desorption were higher.The effect of temperature and concentration on desorption and regeneration of mixed amines was studied.It was found that increasing temperature promotes desorption and regeneration.It is beneficial to desorption and regeneration,and a higher concentration leads to a thickening of the solution.It can inhibit desorption and regeneration to some extent.which is not conducive to desorption and regeneration.So the best desorption and regeneration conditions of DETA:MDEA=7:3 are as follows:temperature 378K,total concentration 15%.SG-DT-1,SG-DT-2 and SG-DT-3 were synthesized by grafting,heterogeneous direct amination and homogeneous direct amination of DETA onto silica gel.And the structure of SG-DT-1,SG-DT-2 and SG-DT-3 were characterized.The absorption effect was also studied.It was found that the adsorption ability was SG-DT-3>SG-DT-1>SG-DT-2.The adsorption property of SG-DT-3 synthesized by homogeneous direct amination method was the best,which is about twice as high as that of SG-DT-1 synthesized by grafting method.It was related to the amount of nitrogen loaded into the material.The higher the nitrogen content,the better the absorbability.The homogeneous direct amination method is a good choice for the preparation of adsorption materials compared with the heterogeneous direct amination method and grafting method.