Boyan ILIEV1, Thomas J.s. SCHUBERT1
1Iolitec Ionic Liquids Technologies GmbH, Heilbronn, Germany
The current process to capture CO2 is based on highly corrosive and volatile aqueous amine solutions, but due to their ability to retain CO2 - both physically and chemically ILs are a good alternative. Although the benefits of ILs includes reduction of both water consumption and release of VOC to atmosphere as well and corrosion of plant components, the main benefit lies in the low energy cost for regeneration.
The use of a particular IL depends mainly on the flue gas composition. As such we have developed different mixtures, e.g. for capture from coal power plants, showing good diffusivity and activity even in the presence of water or others, more stable to oxidation for capture from cement plants. In the case where oxygen and water content in the gas is low, such as from biogas plants, we can use amino-acid based ILs. The use of a pressure swing for regeneration gives an additional choice of ionic liquids and lowers further the energy demand. The so based process is also suitable for direct air capture. All these processes have been tested on a TRL5 level (Figure 1).
Further research activities concentrate on the utilization of so captured CO2 for in situ conversion into other products e.g. formate and methanol also in the presence of ILs. In this case the IL shows great conversion improvement compared to aqueous solutions.
As a company, specialized in the synthesis and technology development in the field of ionic liquids, which has been on the market for 20 years, we have seen the rise of ionic liquids from lab curiosities over lab test materials and now finally to industrially relevant materials for many applications. One of those involves the use of ionic liquids for CO2 capture and conversion and in our talk we will give a short overview of possible solutions and why they might be commercially viable.
 B. Ortloff, F., Roshitz, M., Graf, F., Kolb, T., Ahrens, M., Schubert, T.J.S., Sep. and Purif. Techn. 195, 413–430.