Kinetics Study Of The Reaction Of CO₂ Into Blended Amine Solution And Tertiary Amine Solution Using The Stopped-flow Technique

Recently,because of the rapid development of the global economy,people's dema nd for fossil fuels has increased.Therefore,the increase in energy consumpt ion has led to an increase in global CO₂ emiss io ns,thus increasing the greenho use effect.At present,one of the most wide ly used and most promis ing CO₂ capture techno logy is CO₂ capture techno logy using amine solvent,so furt her optimizat ion of CO₂capture techno logy is t he key to reduce carbon emiss ions.However,the kinet ics and mecha nis m of CO₂ capture by organic a mines are not systemat ica lly perfected,which limits its app licatio n to a certain e xtent.The kinet ics and mechanis m are one of the most important research d irectio ns for the capture of CO ₂ by amine solut ions.Therefore,this article includes the following two aspects.On the one hand,the reaction kinet ics of MEA+DEA mixed solut ion and CO ₂ at293-313 K was measured us ing a stopped-flow k inet ics ana lyzer in t his stud y.The overall react ion rate constant k₀ increases wit h temperature and the amine concentrat ion increase.And the reaction o f MEA-DEA-CO₂-H₂O system is d ifferent in d ifferent M EA and DEA concentrat io ns.The obtained kinet ic data were divided into two groups,na me ly t he DEA low concentrat ion group and the DEA high concentrat ion group.Us ing t he mod ified termo lecular mechanis m to fit a ll the k inet ic data of the two groups respective ly,the result ing kinet ic equatio n can predict the overall reactio n rate constant k₀ well,and the absolute average deviat ion between the experimenta l va lue and the predicte d value is wit hin a suitab le range.AARDs of the DEA low concentrat ion group and the DEA high concentratio n group were 4.71%and3.33%,respect ive ly.The compet it ion and coorperation relat io nship between MEA and DEA in t he process of CO₂ absorption were invest igated in the DEA low concentrat ion group and t he high DEA conce ntrat ion gro up.In the low DEA concentrat ion group,the compet it ion is more obvious.In the high concentrat ion group of DEA,the coorperation relationship is more obvious.On the other hand,the k inet ics of reaction between CO₂-loaded MDEA solut ion and CO₂ at 293-313 K was measured using a stopped-flow apparatus.The overall reactio n rate constant k₀ increases wit h te mperature and the amine concentrat ion increase.The influence of CO₂ loading on the kinet ics of CO₂ absorption in MDEA solut io n was invest igated.It was found that the CO₂ loading affected the hydroxide content in the MDEA so lut io n,which had a great influence on the kinet ics of the absorption of CO₂ in the MDEA so lut io n.The results showed that the hydroxyl were responsib le for the kinet ics.The impact of the hydroxyl to overall k inet ic cannot be ignored.Based on this,a new model for calculat ing t he reaction k inet ics of the MDEA-CO₂-H₂O system was proposed.The kinet ic data were successfully expla ined by the proposed model.The fitted kinet ic equat ion can predict t he total react ion rate constant well.The absolute average deviat ion between t he experime ntal a nd the predicted value is 4.59%.The second-order reactio n k inet ic constants?k₂?of the loaded MDEA-CO₂-H₂O system a nd the unloaded MDEA-CO₂-H₂O syste m obtained in this study were co mpared wit h the literature values,and the k₂ value of the loaded system obtained in t his study was found.The va lues obtained by most of t he different equip ments are in good agree ment,inc lud ing gas-liq uid mass transfer equip ment and rapid-mixing equip ment,ind icating that the mod ified k₂ va lue of the loaded system obtained in this st udy is valid.To obtain intr ins ic kinet ics,this study s uggests the use of CO₂ loaded amine solut ion for the study of tertiar y amine-CO₂-H₂O syste m kinet ics in stopped-flow apparatus.By stud ying t he kinet ics of absorption of CO₂ in a mine solut io n,the rate of absorption of CO₂ by the amine solut ion can be obtained.This provides reliab le data support for the design a nd process simulat ion o f the CO₂ absorbing column in the amine solut ion.At the sa me t ime,the same t ype of amine syste m and CO ₂ can be studied fro m a dyna mic perspect ive,t he mecha nis m of the reaction.This stud y makes the study of t he k inet ics and mecha nis m of amine absorption o f CO ₂ more systemat ic and comprehe ns ive,provid ing re ference and basis for the stud y reaction mechanis m,industrial applications and follow-up research of CO₂ capture by amine.