| At present, the carbon dioxide emissions have been a global environmental problem. The emission of CO2from fossil fuel combustion in power plant is the main resource, accounts for about30%-40%of the global carbon dioxide emissions. Ammonia solution is an inorganic absorbent with low price, relative to the organic amine absorbent, which has the fast absorption rate, the low equipment corrosion rate, the low energy consumption, the high CO2loading capacity.Cerium is an important kind of rare earth resources. At present, it is widely used in various fields such as catalysts, polishing powder, ceramic technology and other fields. Tradition solvent extraction is one of the most effective methods for the extraction of cerium. However, some volatile and toxicity solvents are adopted in the process of traditional solvent extraction, which is not environment friendly. In recent years, Ionic liquids (ILs) using as extraction and separation of metal have attracted much more attention because of its nonflammability, high thermal stability, low vapor pressure, relative to volatile organic solvents.In this work, we investigated CO2capture from flue gas by ammonia solution in coal-fired power plant. The factors, including ammonia mass fractions, gas velocity, liquid velocity and CO2loading capacity, affecting the CO2removal efficiency, overall mass transfer coefficient and ammonia escape have been discussed. We also study the extraction of cerium from nitric acid solutions by the [C10mim][NTf2]. Our works in concrete are mainly as follows:In this research, a continuous CO2absorption apparatus has been developed. We firstly investigated that the relation between the mass fraction of ammonia and removal efficiency. Then, the effect of some factors, including gas velocity, liquid velocity and CO2loading capacity, on removal efficiency are conducted by using3wt%ammonia solution. Experimental results show that with the mass fraction of ammonia and liquid velocity increasing, CO2absorption increase. With the gas velocity and CO2loading capacity increasing, CO2absorption decrease. To investigate the effect of mass fraction of ammonia on overall mass transfer coefficient, experiments were carried out with ammonia solution varied from1to5wt%. We found that the overall mass transfer coefficient is mainly related to the mass fraction of ammonia and liquid velocity. The influence of gas velocity is not so significant. With the CO2loading capacity increasing, the overall mass transfer coefficient decrease.Experimental results show that ammonia escape is mainly depending on the mass fraction of ammonia and liquid velocity. Under the experimental conditions, with the gas velocity increasing, ammonia escape has little effect. With the CO2loading capacity increasing, it could decrease the amounts of ammonia escape. We also found that the ammonia concentration of exhaust gas could greatly decreased by using water.In this article, IL,[C10mim][NTf2] were applied to the extraction of Ce(IV) from nitric acid medium. Important conclusions could be drawn from this work, with the increasing chain length of ILs, extraction efficiency increase. From1to3mol/L nitric acid solutions, higher acidity could favor Ce(IV) from the aqueous phase into IL phase. NaNO3and LiCl are good salting-out reagent for Ce(IV) extraction. Temperature is a very important factor for extraction, and the extraction process is a spontaneously exothermic process, lower temperatures prefer to the Ce(Ⅳ) extraction. The backward extraction of the Ce(IV) was well conducted by sulfuric acid solution. Recycle test proved that sulfuric acid solution as strippant could bring the loss of IL in the stripping. |
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