Capture of CO2 from high humidity flue gas by vacuum swing adsorption with zeolite 13X

Abstract

Capture of CO 2 from flue gas streams using adsorption processes must deal with the prospect of high humidity streams containing bulk CO 2 as well as other impurities such as SO x , NO x , etc. Most studies to date have ignored this aspect of CO 2 capture. In this study, we have experimentally examined the capture of CO 2 from a 12% synthetic flue gas stream at a relative humidity of 95% at 30°C. A 13X adsorbent was used and the migration of the water and its subsequent impact on capture performance was evaluated. Binary breakthrough of CO 2 /water vapor was performed and indicated a significant effect of water on CO 2 adsorption capacity, as expected. Cyclic experiments indicate that the water zone migrates a quarter of the way into the column and stabilizes its position so that CO 2 capture is still possible although decreased. The formation of a water zone creates a "cold spot" which has implications for the system performance. The recovery of CO 2 dropped from 78.5% to 60% when moving from dry to wet flue gas while the productivity dropped by 22%. Although the concentration of water leaving the bed under vacuum was 27%(vol), the low vacuum pressure prevented condensation of water in this stream. However, the vacuum pump acted as a condenser and separator to remove bulk water. An important consequence of the presence of a water zone was to elevate the vacuum level thereby reducing CO 2 working capacity. Thus although there is a detrimental effect of water on CO 2 capture, long term recovery of CO 2 is still possible in a single VSA process. Pre-drying of the flue gas steam is not required. However, careful consideration of the impact of water and accommodation thereof must be made particularly when the feed stream temperature increases resulting in higher feed water concentration.

A review: methane capture by nanoporous carbon materials for automobiles

“…The metal cations in zeolites (i.e., Li, Na, and Al) affect the CH 4 adsorption. CH 4 storage using zeolites has been studied in previous works, mainly with zeolite 5A and zeolite 13X, which show CH 4 storage performance of 2-27 wt% at room temperature and high CH 4 gas pressure [71][72][73][74].…”

Production of molecularly imprinted polymer particles with amide-decorated cavities for CO 2 capture using membrane emulsification/suspension polymerisation

“…In 9 addition, amine scrubbing systems exhibit a low specific interfacial area and require high 10 regeneration energy, which can reduce energy output of the plant by 25-40% [7,8]. 11 Solid adsorbents can be attractive alternatives, because they are nontoxic, nonvolatile and 12 noncorrosive, require lower regeneration energy, and display a higher surface area-to-volume 13 ratio [7,9]. Zeolites can have a high CO 2 capture capacity and high CO 2 -over-N 2 selectivity 14 under atmospheric conditions [10,11].…”

“…Zeolites can have a high CO 2 capture capacity and high CO 2 -over-N 2 selectivity 14 under atmospheric conditions [10,11]. However, the presence of moisture in flue gases 15 greatly reduces their capture capacity and requires higher regeneration temperatures, resulting 16 in higher energy penalties [12]. 17 Metal organic frameworks (MOFs) show high CO 2 capture capacity at elevated pressures 18 [13], but under typical conditions of post-combustion carbon capture, their capture capacity is 19 reduced, especially in the presence of moisture, NO x and SO x [10,14].…”

Comprehensive analysis on the performance of an IGCC plant with a PSA process integrated for CO2 capture

“…This is the case for a pre-combustion application. Other advantages of activated carbons over zeolites are the lower costs [8] and the higher resistance to water presence in the gas mixture [8,29,30]. Material science is very active in the research of new adsorbents with enhanced characteristics for CO2 separation [31][32][33][34].…”