Adsorption CO₂ From Flue Gas By New Solid-amine

Extensive efforts have been devoted in CO2 capture and storage, especially for CO2 separation from flue gas. Adsorption is considered as one of the most promising methods to CO2 capture. And new adsorption separation technologies are actively pursued to develop a competitive alternative for the removal of CO2 from flue gas application. In this paper, a series of solid amine were prepared by impregnating the new mesoporous silica with the poly-amine dissolved in ethanol. Characteristics of solid amine and dynamic adsorption/desorption performance were investigated. The main conclusions of this work are drawn:1. The solid amines were prepared by impregnating mesoporous silica KIT-6 and SBA-16 with polyethyleneimine (PEI) or tetraethylenepentamine (TEPA) dissolved in ethanol. The mesoporous structure of KIT-6 and SBA-16 are preserved after loading TEPA (PEI). Surface area, pore size and pore volume of solid amine decrease with the increasing of TEPA (PEI) loading. And the CO2 adsorption capacity increases with the increasing of loaded amine. The maximum amount of amine loading in the pore channel are about 50 wt.% and 37 wt.% for KIT-6 and SBA-16, respectively. The CO2 adsorption capacity rises with the raising temperature. The maximum adsorption capacity is 3.2mmol·g-1 at 343K for KIT-6/TEPA. The adsorption capacity drops slightly after dozens of adsorption/desorption cycles. The solid amine exhibits excellent CO2 adsorption/desorption performance.2. To obtain dynamic adsorption capacity and breakthrough curve, the CO2 adsorption experiments were performed in fixed bed. The dynamic adsorption capacity increases from 1.9 mmol·g-1 to 3.1 mmol·g-1 when the temperature increases from 293K to 343K. However, the dynamic adsorption capacity reduces to 2.8 mmol·g-1 at 353K. And the adsorption rate is 0.022mmol·min-1 for each temperature. The adsorption of CO2 on KIT-6/TEPA is chemisorption. And the ratio of chemisrotion capacity is about 97.2% of total adsorption capacity. Carbon dioxide adsorption isotherms of KIT-6/TEPA exhibits a type I at various temperatures. The average isosteric heat of adsorption is 43.8 kJ-mol"1 3. The adsorption capacity is improved by the presence of water vapor in the simulated flue gas. The adsorption capacity increases from 2.9mmol·g-1 to 3.2mmol·g-1 when the relative humidity rise from 0% to 37%.The adsorption capacity is slightly inhibited by the presence of sulfur dioxide when the concentration of sulfur dioxide ranges from 0 ppm to 300 ppm. As to other pollutant in the flue gas, the adsorption capacity is nearly uninfluenced by nitric oxide during a range of concentration up to 400 ppm. The adsorption capacity maintains almost the same after ten cycles of adsorption/regeneration in the adsorption condition of 10vol.% CO2,100 ppm SO2,200 ppm NO,100% relative humidity and regeneration condition of a temperature of 393K. Experimental breakthrough curves are in excellent agreement with the dynamic model.4. Regarding the regeneration performance of CO2 adsorbent, the solid amine is completely regenerated within 11min during 10 recycles of adsorption/desorption. When the sample is desorbed at 373 K at a. flow rate of 100 cm3·min, at least about 21 mole N2 are required for desorbing lmole of CO2. The vacuum desorption experimental shows that the adsorbent could be totally regenerated in 20min, and the maximum desorption rate of 1.02 mmol·min-1 was achieved in the pressure of 5KPa at 393K. The necessary consumption energy is about 1.41 MJ·kg-1CO2.