Membranes carbon capture

Keywords Natural gas, carbon capture, membrane technology, sorption based separations, separation enhanced reactors... 

The combination of a less-constrained ASU for oxygen production and a carbon capture process using membranes instead of amine solvents can conduce to a minimal energy requirement associated with an oxygen purity ranging between 0.5 and 0.6 molar fraction. 

The following example illustrates the potential of membrane-separation processes for precombustion carbon capture in an IGCC. This approach avoids using an expensive air-separation unit (asu) or a difficult-to-implement high-temperature mixed-ion conducting membrane process however, it still enables capture of C02 at purities suitable for commercial use or sequestration. 

These routes are connected with carbon capture with subsequent sequestration. Another approach is to avoid the production of CO2 emissions altogether through increased industrial energy efficiency and thus a lower energy consumption. The topic of this chapter, oxygen production, is related to the last two points. In the first three routes mentioned above, three different methods can be used for the separation of CO2 and the other gases absorption in solvents, separation by membranes and adsorption or absorption on or in a sorbent. 

Marano J, Cifemo J. Membrane selection and placement for optimal co2 capture from igcc power plants. Fifth annual conference on carbon capture sequestration, Alexandira, VA, 2006. 

Lima F. V., Daoutidis P., Tsapatsis M., Marano J. J. 2012. Modeling and optimization of membrane reactors for carbon capture in Integrated Gasification Combined Cycle units. Industrial and Engineering Chemistry Research 51(15) 5480-5489. 

The development of membrane materials for CO2 capture from flue gas has received much attention during the last decade, clearly as a function of the concern about climate change and the need for carbon capture and sequestration (CCS). Many papers have been published (here only a few are being referred to [10,188-191]), but the major challenges for this membrane application are durability of the material over time, as there will be exposure to SO and NO, and very high separation performance needed (flux and selectivity) in order to decrease the needed membrane area for the huge volume gas streams. Very few pilots have been tested around the world only two are mentioned here (i.e., from MTR and NTNU). The number of pilots is expected to increase over the next few years. 

Noble RD. Achieving a 10,000 GPU permeance for post-combustion carbon capture with RTIL-based membranes, DOE NETL CO2 Capture Technology Meeting, Pittsburg, PA, 2011. 

Besides the investigation of monolithic carbons with well-ordered mesoporosity as CO2 sorbents, the synthesis of ordered mesoporous carbon films for CO2 capture (membrane gas separation) also attracts much interest. Noticeably, highly ordered mesoporous carbon with cubic Im3m symmetry has been synthesized successfully via a direct carbonization of self-assembled F108 (EOi32P05oEOi32) and RE composites obtained in a basic medium of non-aqueous solution [66]. Dai et al. [49] demonstrated a stepwise self-assembly approach to the preparation of large-scale, highly ordered nanoporous carbon films (Eig. 2.14). 

Sulfur dioxide has also been reported to plasticize polymeric membranes, which produces a more rubbery material and increases the diffusivity of penetrant gases [26-28]. Plasticization also reduces the mechanical integrity of the membrane, meaning it is more likely the membrane will rupture. However, plasticization is a strongly pressure dependent phenomenon, for example it has been reported in polyvinylidene membranes to occur at SO2 pressures greater than 10 psi [29]. For many of the processes in carbon capture, such high partial pressures of SO2 are not observed (Table 11.1), and therefore only minor plasticization by SO2 is likely to occur. 

Helmi, A., Gallucci, F. and Van Sint Annaland, M. (2014) Resource scarcity in palladium membrane applications for carbon capture in integrated gasification combined cycle units. International Journal of Hydrogen Energy, 39 (20), 10498-10506. 

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