Abstract
For improving the CO2 adsorption capacity of solid-supported amines, five commercial porous supports have been selected and impregnated with tetraethylenepentamine (TEPA), and their CO2 adsorption performances have been evaluated using a fixed-bed reactor coupled with mass spectrometry. For solid-supported amines, CO2 adsorption capacities coincide with the texture characterization of the adsorbent supports (mesoporous alumina, montmorillonite, silica gel, porous resin, MCM-41 molecular sieve), and the optimum TEPA loading amount is mainly affected by the pore volume. The mesoporous supports were found to be more conducive to uniform loading of organic amine, with more than 370 mg/g CO2 adsorbed per unit TEPA. Other components in flue gas, especially H2O, favor CO2 adsorption on solid-supported amines. SO2 inhibited the CO2 adsorption, which was mainly attributable to the strong and irreversible binding of SO2 on some amine sites. NO had little effect on CO2 adsorption. Thermal stabilities of solid-supported amines have been tested based on thermogravimetry curves, and the main weight loss peak for TEPA appears at 513 K for solid-supported amines. Linear and step regeneration modes have been compared, revealing that the temperature for step regeneration is 37 K lower than that for the linear regeneration mode. Moreover, the desorption peak area for the step regeneration mode is 20% higher than that for the linear regeneration mode, indicating that the step regeneration mode can be used in practical applications, to reduce energy consumption during regeneration.
Highlights
CO2 is the main component of greenhouse gases; the exacerbation of the greenhouse effect causes increased atmospheric temperature and species’ extinction.[1]
MCM-41 has the largest specific surface area (SBET) of 1173.6 m2/g and pore volume (VT) of 1.024 mL/g, MMT has the smallest SBET of 94.1 m2/g, VT of 0.125 mL/g, and D0 of 3.38 nm, and porous resin (PR) has the largest D0 of 11.652 nm
In accordance with the pore volumes (Table 1), for mesoporous or macroporous supports, the optimum TEPA loading amount is mainly affected by the pore volume and the
Summary
CO2 is the main component of greenhouse gases; the exacerbation of the greenhouse effect causes increased atmospheric temperature and species’ extinction.[1]. CaoffinncietnytrfoatrioCnOa2ndunindetrhefluperegsaesncceonodf imtioonisst,uerev.e1n5 at a The most widely used organic amines are tetraethylenepentamine (TEPA) and polyethylenimine (PEI).[16] Solid-supported amines have a high CO2 adsorption capacity and a high CO2 selectivity and can overcome the limits and drawbacks of currently used technologies (e.g., corrosion, energy-efficient regeneration, oxidation, or degradation of liquid amines).[17]. The current research studies on solid-supported amines for CO2 adsorption are mainly focused on two points: to improve the CO2 adsorption capacity and to improve the thermal stability and reduce the regeneration energy consumption of the adsorbents. To improve the CO2 adsorption capacity of solid-supported amines, five commercial porous supports, mesoporous alumina (MA), montmorillonite (MMT), silica gel (SG), porous resin (PR), and MCM-41 molecular sieve (MCM-41), were selected . Considering that 71% of the CO2 emissions arise from coal-fired flue gas in China,[25,26] the effects of SO2, NO, and H2O in flue gas on CO2 adsorption were studied
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