Removal Of Trace Amount Of C₂H₆ From CO₂ By Adsorption

Recovery of CO₂ is significant for both reduction in a green house gas and best utilization of carbon resource.However,a captured CO₂ stream is not easy to be deep-purified because some impurities,such as C₂H₆,in the CO₂ stream are difficult to be removed.The purpose of this study is to develop efficient adsorbents for removing C₂H₆ impurity from CO₂ stream.Firstly,screening and evaluation of adsorbents,effects of the different kinds of adsorbent on adsorption performance were investigated,effects of the physical configuration and surface properties of activated carbon on adsorption performance were analyzed.It was showed that activated carbon is the best adsorbent in removal of trace amount of C₂H₆ from CO₂,because of its high specific area,abundance of microporous,a few mesopore and nonpolar surface.Then,modified with activated carbon through four methods:modified by acid and alkali, oxidizing modification,reduction modification and metal ions modification.Adsorption performances of all kinds of modified activated carbons were evaluated.Effects of impregnate kinds,impregnate concentration,treatment temperature and treatment time on the adsorption performance of activated carbon were investigated.It was showed that modified by acid and alkali,oxidizing modification and reduction modification can improve the adsorption performance of activated carbon,the activated carbon modified by 5%HC1 had a high capacity.Activated carbon modified with metal ions make against removal of C₂H₆ from CO₂.Lastly,effects of flow rate,particle size,bed thickness,adsorption temperature and C₂H₆ concentration on the breakthrough curve,adsorption capacity,LUB and Q were investigated. Effects of regeneration temperature,regeneration time and regeneration times on adsorption performance were investigated.It was showed that LUB decrease with the decrease of in flow rate,particle size and bed thickness,the adsorption quantities of ethane on activated carbon decrease with the increase of adsorption temperature and decrease of C₂H₆ concentration.Gas heating regeneration was effective regeneration method,activated carbon also has effective adsorption performance after repetitious regeneration,when regeneration temperature is 120℃,and regeneration time is 180min.