Study On Gas Adsorption Characteristics In CO₂ Capture And Storage

The large consumption of fossil fuels and the unlimited emissions of CO₂ have caused a sequence of environmental problems,such as global warming,sea level rise and extreme weather events.Therefore,reducing the CO₂ emissions is imperative.Compared with the methods like afforestation and developing renewable clean energy,CO₂ capture,utilization and storage?CCUS?technique can significantly reduce the CO₂ concentration in the atmosphere in a short period of time.Adsorption with solid sorbents is one of the most promising options for CO₂ capture.Loading organic amine with high amino density and low price on the surface of porous material,which has developed pore structure,large specific surface area and good thermal stability,is a good way to improve the adsorption capacity and selectivity of CO₂.For the process of CO₂capture,the CO₂ adsorption capacity of aminated graphite oxide?AGO?was studied in this paper.Five different adsorbents of graphite oxide?GO?modified by tetraethylenepentamine?TEPA?were developed with raw TEPA/GO ratios of 0,3,5,10,and 50 wt%.A series of characterizations were carried out,including elemental analysis,SEM analysis,FT-IR analysis,BET analysis and pore size distribution.Subsequently,the CO₂ adsorption capacities of the 5different samples were investigated at 25,40,70,and 90°C over a wide range of pressures?0.1-5 MPa?.It turned out that the adsorption capacity of the pristine GO sample decreased as the temperature rose.Besides,with increasing pressure,the excess adsorbed amount of the pristine sample increased significantly,with a peak near 3 MPa followed by a sequential decrease.The 3%and 5%AGO samples showed better adsorptivity than that of the pristine GO sample,while the 10 and 50%AGO samples exhibited worse performance.Furthermore,for the 3%and 5%AGO samples,the adsorption capacity was markedly improved at 70°C in comparison with the pristine GO sample,suggesting that these are appropriate temperatures and TEPA/GO ratios for CO₂ capture.CO₂ enhanced shale gas recovery?CO₂-ESGR?technique not only can achieve enhanced CH₄ recovery,but also can realize CO₂ safe storage.For the process of CO₂ enhanced shale gas recovery,the CO₂/CH₄ adsorption property on shale was studied in this paper.A series of characterizations were carried out,including elemental analysis,BET analysis and pore size distribution.After that,the CO₂ adsorption capacity of shale was investigated at 20,40,60,and 80°C over a wide range of pressures?0.1-5 MPa?,while the CH₄ adsorption capacity was investigated over a wider range of pressures?0.1-15 MPa?.It turned out that the relatively good adsorptivity for CO₂ was displayed when the experimental pressure was less than 5 MPa,which is beneficial to the implement of CO₂ enhanced shale gas recovery?CO₂-ESGR?.Whereas better adsorptivity for CH₄ was displayed with increasing pressure.When the pressure become too high,the density of CO₂ would increase significantly,resulting in difficulty to be adsorbed in pore structure on the surface of the shale,which would cause the adsorption capacity reduce significantly.