(127c) Post-Combustion CO2 Capture Via Formation of Aminosilicone Carbamate Salt Powders in Spray Dryers

ABSTRACT BODY: A particular low viscosity aminosilicone compound terminated with a primary amine on each end (designated as GAP-0) has been identified that reacts very quickly with gaseous CO2 to form a white solid carbamate salt. If the stoichiometric amount of CO2 reacts with GAP-0, the ratio of the mass of CO2 in the GAP-0 carbamate salt to the mass of the GAP-0 is 18%.

Therefore, pure liquid GAP-0 was displaced through the nozzle of a lab-scale spray dryer, where the resultant droplets reacted with CO2 gas flowing co-currently through the spray chamber. The carbamate salt powder formed in the chamber was separated from the CO2-depleted gas stream in a cyclone separator. (Note the while a spray "dryer" apparatus was used, the formation of the solid powder is actually due to the reaction between the GAP-0 liquid and CO2 gas; it is not due the evaporation of a liquid.)

We propose that this process may serve as a novel means of CO2 capture that eliminates the need for a solvent. Therefore it is likely to reduce regeneration heat requirements because there would be no requirements for the sensible and latent heat demands associated with an aqueous or non-aqueous solvent. The carbamate salt powder would be collected from the bottom of the cyclone separator and then heated to release the CO2, allowing the GAP-0 liquid to be reclaimed. The GAP-0 would then be recycled to the nozzle at the top of the spray chamber, while the CO2 would be compressed for sequestion.

The properties of the carbamate salt powder product were determined, including particle size (SEM), melting point (DSC), heat required for regeneration (DSC), phase behavior and rate of CO2 release as a function of temperature, pressure, time and ambient gas composition (variable volume PVT cell), and weight loss due to evaporation and CO2 release as a function of temperature in an inert argon atmosphere (TG MS), and in a CO2 atmosphere (TG).