Cycle Development and Design for CO 2 Capture from Flue Gas by Vacuum Swing Adsorption

Cooperative Research Centre for Greenhouse Gas Technologies, Department of Chemical Engineering, Monash University, Victoria 3800, Australia.
Environmental Science and Technology (Impact Factor: 5.33). 02/2008; 42(2):563-9. DOI: 10.1021/es0706854
Source: PubMed

ABSTRACT CO2 capture and storage is an important component in the development of clean power generation processes. One CO2 capture technology is gas-phase adsorption, specifically pressure (or vacuum) swing adsorption. The complexity of these processes makes evaluation and assessment of new adsorbents difficult and time-consuming. In this study, we have developed a simple model specifically targeted at CO2 capture by pressure swing adsorption and validated our model by comparison with data from a fully instrumented pilot-scale pressure swing adsorption process. The model captures nonisothermal effects as well as nonlinear adsorption and nitrogen coadsorption. Using the model and our apparatus, we have designed and studied a large number of cycles for CO2 capture. We demonstrate that by careful management of adsorption fronts and assembly of cycles based on understanding of the roles of individual steps, we are able to quickly assess the effect of adsorbents and process parameters on capture performance and identify optimal operating regimes and cycles. We recommend this approach in contrast to exhaustive parametric studies which tend to depend on specifics of the chosen cycle and adsorbent. We show that appropriate combinations of process steps can yield excellent process performance and demonstrate how the pressure drop, and heat loss, etc. affect process performance through their effect on adsorption fronts and profiles. Finally, cyclic temperature profiles along the adsorption column can be readily used to infer concentration profiles-this has proved to be a very useful tool in cyclic function definition. Our research reveals excellent promise for the application of pressure/vacuum swing adsorption technology in the arena of CO2 capture from flue gases.

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    • "Indeed, the Si/Al ratio and the number/nature of extraframework cations can play a major role in controlling the CO 2 adsorptive properties [22] [23]. "
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    ABSTRACT: Among all the post-combustion technologies, adsorption processes on solid sorbents are attractive due to their low energy requirements. Great interest is focused on ultra-fine materials, whose chemicophysical properties can be tuned at the molecular level. However, the capture capacity of these fine materials strongly depends on the technology adopted for the adsorption tests. Common techniques, such as thermogravimetric analysis or fixed bed operation, end up underestimating it, since these fine powders are organized in structures (aggregates), which can be difficultly permeable to the gaseous phase. Therefore, the choice of the proper adsorption technique becomes crucial. In this framework sound-assisted fluidization has already been proved to maximize the CO2 adsorption capacity of fine sorbents with respect to common technologies, due to the higher exploitation of the exposed surface. The aim of the present work is, therefore, to compare the adsorption performances of different materials (two activated carbons, two zeolites and a metal organic framework) under sound-assisted fluidization conditions (140 dB–80 Hz) in order to maximize the gas–solid contact efficiency and, in turn, minimize the limitations to the intrinsic adsorption capacity of the sorbents. All the tests were performed at ambient temperature and pressure with values of CO2 concentration typical of flue gases (5–10 vol.%). The different behaviors exhibited by the materials were explained on the basis of their textural properties. In particular, the microporosity falling in the range of 8.3–12 Å strongly affects the CO2 adsorption performances under the investigated operating conditions.
    22nd International Conference on Fluidized Bed Conversion (FBC), Turku (Finland); 06/2015
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    • "Thus, the development of a promising material that would adsorb CO 2 with a high capacity and the ability to be regenerated with a low energy input will certainly enhance the competitiveness of an adsorptive separation system in a flue gas treatment [7]. The cyclic adsorption–desorption operation was commonly carried out by means of pressure swing adsorption (PSA), temperature swing adsorption (TSA), or vacuum swing adsorption (VSA) with many kinds of solid materials including carbon based adsorbents [8] [9] [10] [11] [12] [13] [14] [15] and zeolite based adsorbents [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27]. In order to make CO 2 desorption from the spent adsorbents become more practical in the field, a combination of TSA and VSA (TVSA) was employed to reduce desorption time of CO 2 from the spent amine-loaded carbon nanotubes (CNTs) [12] [28] and spherical mesoporous silica particles (MSPs) [29] as compared to TSA or VSA. "
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    ABSTRACT: Abstract A dual-column temperature/vacuum swing adsorption (TVSA) with 3-aminopropyltriethoxysilane-loaded carbon nanotubes (CNT(APTS)) was built to study cyclic CO2 capture from gas streams. The working CO2 capacities and the characteristics of CNT(APTS) were preserved through 100 TVSA cycles under dry or wet conditions, displaying the multi-cycle stability of CO2 capture with CNT(APTS). The cyclic working CO2 capacity of CNT(APTS) was notably enhanced in the presence of saturated water vapor in the gas stream at 25 °C which gives relatively high desorbed CO2 concentrations (∼67%). These results suggest that a dual-column TVSA with solid CNT(APTS) has the possibility to be a promising CO2 capture technology, especially in the post-flue gas desulfurization in which saturated water vapor is present in the flue gas.
    Applied Energy 01/2014; 113:706 - 712. DOI:10.1016/j.apenergy.2013.08.001 · 5.61 Impact Factor
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    • "One technology for capturing CO 2 is the use of adsorption processes. Over the past few years, we have experimentally investigated the capture of CO 2 from synthetic dry air-CO 2 blended gas streams containing 10-12% CO 2 by our VSA (vacuum swing adsorption) process and achieved good technical performance (CO 2 purity > 95% and recovery > 80%) [1]. These results are largely achieved with zeolite13X adsorbents which is the most common commercial adsorbent used for separating CO 2 from dry simulated flue gases. "
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    ABSTRACT: All flue gases contain water vapour along with carbon dioxide, nitrogen, etc. Vacuum Swing Adsorption (VSA), which has been successfully studied for post-combustion dry CO2 capture in our group, is strongly affected by the overwhelming competitive adsorption of water vapour on CO2 adsorbents. In this study, breakthrough experiments have been conducted to measure the single/binary adsorption isotherm data of CO2 and water vapour on zeolite 13X and a proprietary alumina-based adsorbent alumina CDX to study the competitive adsorption effect on each other. The CO2 adsorption data are well represented by the Dual site Langmuir isotherm equation. Based on the above understanding, a single column multilayered VSA unit was used with a guard-bed layer of superior desiccant and a main layer of 13X to simultaneously remove water (3–4% by volume) and capture CO2 (10–12%) at 30 ∘C within the same process. In this study, activated alumina CDX was selected as the appropriate pre-layer. Furthermore, we have investigated the effects of operating parameters on the multilayered CO2/H2O VSA performance. The water front was accurately located in the bed and the interaction of CO2 and water vapour indicates a clear indication of a water loaded zone and a CO2 loaded zone. The result demonstrates that water front has been successfully held in the pre-layer and CO2 product purity of 76.9% and purity of 67% were achieved for the double layered single column CO2/H2O VSA.
    Energy Procedia 02/2009; 1(1):1123-1130. DOI:10.1016/j.egypro.2009.01.148
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