Carbon dioxide absorption in a technical-scale-plant utilizing an imidazolium based ionic liquid

In order to decrease the carbon dioxide (CO2) content of gas streams to reach environmental or sales gas requirements, a series of different techniques have been established over the years. For example, in natural gas processing, aqueous amine solutions are commonly used as a washing media. A category of new fluids, ionic liquids (ILs), shows certain advantages compared to standard technologies, like non-volatile character and the absence of aqueous solutions. A great amount of research into CO2 solubility in ILs in general has been performed over the last years, fewer in high pressure solubility. Nearly none have reached a state beyond laboratory scale. This paper presents the final experiments from a feasibility study, namely high pressure absorption of CO2 from an inert component and the respective desorption by using columns at technical scale.

The used IL is non-toxic, stable to hydrolysis and can practicably and reasonably be produced industrially with a novel high quality synthesis route.

Measuring the pressure equilibrium data at different temperatures and generation of the corresponding diagrams was the basis for the column experiments. A fundamental point was to identify which phase flows disperse together with the consequent impact on the process. The investigation of the recycling behavior, as a sequence of absorption and desorption cycles, was a very important part of the project. Hence, it was possible to improve the balance point and the load line. The results promise the application of the novel process on an industrial scale soon.