CO₂ Absorption Tests Of Blended Amines And Tertiary Amine Solutions With CaCO₃、MgCO₃

The greenhouse effect caused by a large amount of carbon dioxide emissions has led to global warming,rising sea levels,melting glaciers and other environmental problems,seriously polluting the atmosphere,threatening public health and damaging environmental safety,which not only affects The global ecosystem balance threatens the human generation environment.CO₂ is the most influential gas to the global warming,because coal is still the most widely used and low-cost source of electricity in the world,and its main source of emissions is coal-fired power generation.Therefore,effective control and reduction of pollutant CO₂ emissions is an urgent task.It is important to capture and safely store CO₂ emissions before they reach the atmosphere.As the government’s demand for lowering carbon emissions becomes more intense,CO₂ capture and storage（CCUS）technology and its industrial applications are among the most hot engineering directions in the world in the past 10 years and in the next 10 years.Post Combustion Capture（PCC）technology can be directly used to capture CO₂ from traditional power plant flue gas.It is one of the most widely used and most promising processes.However,this method still has enormous challenges.The absorption rate of CO₂,the corrosion of equipment,the huge energy consumption of regeneration,etc.need to be solved urgently.As a result,many researchers have begun to move from a single amine solution to a mixture of different amine solutions or to develop efficient new absorption solvents to solve some of the problems faced.In this paper,the amine solution was used as the absorbent to study the CO₂absorption.The solid alkaline earth metals Ca CO₃ and Mg CO₃ were used as catalysts to study the catalytic properties of CO₂ absorption in the secondary mixed amine and single tertiary amine solvent.The main contents of the study and the conclusions are as follows:（1）Catalytic absorption of mixed amine experiments:The MEA-DEA blended amine solvents have been a hot research topic recently.In a batch process,5.0 mol/L MEA solvent was used as benchmark with the aid of solid chemicals Ca CO₃ and Mg CO₃.This study focused on the absorption efficiency tests of 5mol/L MEA+DEA blended solvents（4+1,3+2,2+3,1+4 mol/L）.Catalytic absorption experiments were carried out in a condensing reflux device,and the effects of the comparison on the absorption properties of CO₂ were analyzed.The absorption profiles and initial absorption rates were plotted to select the optimized mix ratio.The results indicated that 1.0+4.0～2.0+3.0 M MEA+DEA had good performance in absorption with the aid of Ca CO₃.It contained 72-77%of the absorption efficiency but only 46-50%of the heat duty compared with 5M non-catalytic MEA.In this region,the synergistic effect of the mixed amine solution of MEA+DEA is relatively strong.After considering the two aspects of absorption and desorption,it was found that under the action of the solid base catalyst Ca CO₃,two types of mixed amine solutions（1.5+3.5 M and 2.0+3.0 M MEA+DEA）has relatively high absorption parameters and desorption parameters,and can be used as an alternative solution in the industry due to absorption of CO₂.These solvents will have great advantages on both sides of the desorption column and the absorption tower,with very low heat load and relatively fast Absorption rate.（2）Catalytic absorption of a single tertiary amine experiment:Studies of catalytic CO₂ absorption is completed of two well-performed tertiary amines:diethylmonoethanolamine（DEEA）and 1-dimethylamino-2-propanol（1DMA-2P）,with the aid of Ca CO₃ and Mg CO₃ in the absorption process.The batch process was used for CO₂ absorption with solid alkalis.Catalytic absorption experiments were carried out in a condensing reflux apparatus to investigate the CO₂ absorption performance under catalytic conditions.The CO₂ equilibrium solubility and p Ka were also measured at 293K with results comparable to literature.Through a series of catalytic experiments,it was found that under non-catalytic/catalytic conditions,the mixed amine solution and tertiary amine solution have completely different CO₂ absorption effects and mechanisms,but they can effectively enhance the CO₂ absorption rate of the amine solution and accelerate mass transfer.