NEW SOLVENTS BASED ON AMINO-ACID SALTS FOR CO_2 CAPTURE FROM FLUE GASES

摘要

This paper discusses the use of amino-acid salt solutions as an alternative to amine based solutions. Important solvent characteristics are reactivity, cyclic loading, temperature stability, stability towards oxygen and binding energy. As a first option amino-acid salt solutions are particularly suitable for application with poly-olefin membrane contactors. Membrane contactors provide the opportunity for reduction of the size of the absorber and result in modular scale up to the required size. This will reduce investment costs, provided membrane module costs are low. A second option is provided by the interesting feature of several amino-acid salts to produce precipitates when absorbing CO_2. It has been shown that this allows the driving force to be maintained at increased loading. The increased loading also leads to low energy consumption for solvent regeneration. To achieve this, however, the heat exchanger needs to be integrated into the regenerator. Results of a preliminary economic evaluation are presented. It is shown that this new technology has the potential to half the investment costs and half the energy consumption for regeneration. The excellent perspective has resulted in further fundamental research to provide a firm basis for the novel capture process based on precipitating solvents.