(654a) Effects of Inorganic Salts On Absorption of Carbon Dioxide and Oxygen for Alkanolamine Solution Containing Diethyleletriamine and Piperazine in a Rotating Packed Bed

In this work, CO₂ was capture from a gas stream containing 10% CO₂ using an alkanolamine solution containing 15wt% diethylenetriamine (DETA), 15wt% piperazine (PZ) and inorganic salt in a rotating packed bed (RPB). After the study of the addition of potassium chloride (KCl), sodium chloride, lithium chloride, and lithium bromide in the solution on absorption of CO₂ and O₂, KCl was found to be the most effective inorganic salt for the CO₂ capture efficiency, resulting from the longer ionic radius possessed by KCl. Furthemore, the addition of KCl would lower the dissolved oxygen (DO) amount in the solution and yield the same effect as the oxygen scavenger Na₂SO₃. Due to KCl was not consumed by DO, this addition led to no generation of the degradation products created from Na₂SO₃. The effects of gas flow rate, KCl concentration and temperature on CO₂ capture efficiency and DO were examined by a 2³ factorial design. Gas flow rate was found to be the most significant factor affecting CO₂ capture efficiency followed by temperature and KCl concentration, while temperature was the most significant factor affecting DO followed by gas flow rate and KCl concentration. The optimum operation condition achieving higher CO₂ capture efficiency and lower height of transfer unit in the CO₂ capture process was determined by the response surface methodology. The regeneration energy of 15wt% DETA+15wt% PZ solution containing 1.5 m KCl was found to be lower than that of the solution without KCl since the vapor pressure and heat capacity of the solution were reduced, in a subsequence vaporization heat and sensible heat were reduced as well.