Development of CO2 capture method via polyurethane-amine sorbent in VSA

With increases in extreme weather and global temperatures, research is delving into CO2 capture to help reverse climate change. This project explored utilizing vacuum swing adsorption (VSA) for CO2 capture and release. VSA uses a sorbent, in this case amine sorbents, to capture CO­­2 from air and subsequently removes it via vacuum. Polyurethane (PU) foam was investigated as a potential matrix for amine sorbents to increase exposure of CO2 capturing amines to air by utilizing its porous structure. PU mixing studies were conducted to determine the feasibility of mixing PU foam with amines and coating foams with amine solutions by studying the effects they might have on the foam matrix structure. The amines tested include polyethylenimine (PEI), tetraethylenepentamine (TEPA), and diethylenetriamine (DETA). The impact of modifying the amines via methods such as saturation with CO2 and poisoning with acids were explored with regard to their effect on PU foam structure and expansion. Many interactions between amines and PU caused the resulting foam to collapse, having little to no porous structure. However, a 6.5 wt% of 1:1 H2O and TEPA mixture added to PU was determined to provide better internal structure and solvent uptake than commercial closed cell foam. A CO2 capture vacuum unit was designed and constructed for VSA. FTIR analysis was conducted in-situ with the unit to observe CO2 adsorption and desorption. Observations verified the method of CO2 capture and measurement as an effective method. It also showed that some amine was pulled from the PU matrix in the vacuum, so future work will continue to improve amine retention. This project developed sorbent samples with analysis of amine-PU interaction effects, a CO2 unit for VSA, and a method for in-situ analysis of CO2 adsorption and desorption