CO2 separation membranes

G. Blizzard, D. Parro, K. Homback, CO2 separation membranes a critical part of the Mallet CO2 removal facility, in Proceedings of the Presentations at Laurance Reid Gas Conditioning Conference, Norman, OK (2005). 

Wade J L and Lackner K S (2007), Transport model for a high temperature, mixed conducting CO2 separation membrane , 5o/t[Pg.603]

Taniguchi, I., Duan, S., Kazama, S., Fujioka, Y. (2008). Facile fabrication of a novel high performance CO2 separation membrane immobilization of poly(amidoamine) dendrimers in poly(ethylene glycol) networks. Journal of Membrane Science, 322, 277—280. 

The manufacture of DPMs based on infiltrated molten carbonates in the porosity of perovskite membranes constitutes the most recent and innovative application of perovskites for CO2 capture. Since the first studies reported by Wade and coworkers [33] and Lin and coworkers [34], many efforts have been made to develop stable high-flux membranes for CO2 separation. Table 39.5 collects the most remarkable results, whereas Figvue 39.12 plots the permeance versus permeability plots for dual-phase perovskite-carbonate materials compared with low-temperature CO2 separating membranes (zeolites and MOFs/ZIFs). 

High performance composite CO2 separation membranes./. Membr. Set, 471, 211-218. 

To date, many kinds of CO2 separation membranes have been reported, including polymeric membranes, composite membranes, and facilitated transport membranes. Further improvements in membrane performance depend on effective CO2 separation materials, and one candidate is ILs. It has been reported that ILs have good CO2 selectivity, suggesting that they may be a possibility for the development of new CO2 separation materials. Since ILs are liquid at room temperature, it is necessary to affix ILs to appropriate support materials. Supported IL membranes have been prepared by impregnation of commercial porous polymer films with 1-n-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([hmim][Tf2N]) and have obtained good C02/He separation properties [40]. Recently, electrospun Nafion/polyethylene oxide (PEO)-supported IL membranes were fabricated for CO2 separation [41]. In this composite membrane, the electrospun Nafion/PEO material acted as a gutter layer for ILs and PEO was added to form clean nanofibrous... 

We have been studying the novel process for CO2 separation named membrane/absorption hybrid method. The advantages of this process are that high gas permeance and selectivity were obtained. The concept of this process is shown in Fig. 1. Both feed gas and absorbent solution are supplied to the inside of hollow fibers. While Ae liquid flows upward inside the hollow fibers, absorbent solution absorbs CO2 selectively and it becomes a rich solution. Most of rich solution permeates the membrane to the permeate side maintained at reduced pressure, where it liberated CO2 to become a lean solution. Compared to a conventional gas absorption... 

Selective gas permeation has been known for generations, and the early use of palladium silver-alloy membranes achieved sporadic industrial use. Gas separation on a massive scale was used to separate U from U using porous (Knudsen flow) membranes. An upgrade of the membranes at Oak Ridge cost 1.5 billion. Polymeric membranes became economically viable about 1980, introducing the modern era of gas-separation membranes. H2 recovery was the first major application, followed quickly by acid gas separation (CO2/CH4) and the production of N2 from air. 

CO2 Separation Using a Thermally Optimised Membrane. This project aims to manufacture a high-temperature polymer membrane with better separation capabilities than current polymer membranes. The project focuses on the separation of CO2, methane, and nitrogen gases in the range of 100 to 400°C. 

The discussion directly following Eq (6) provides a simple, physically reasonable explanation for the preceding observations of marked concentration dependence of Deff(C) at relatively low concentrations. Clearly, at some point, the assumption of concentration independence of Dp and in Eq (6) will fail however, for our work with "conditioned" polymers at CO2 pressures below 300 psi, such effects appear to be negligible. Due to the concave shape of the sorption isotherm, even at a CO2 pressure of 10 atm, there will still be less than one CO2 molecule per twenty PET repeat units at 35°C. Stern (26) has described a generalized form of the dual mode transport model that permits handling situations in which non-constancy of Dp and Dh manifest themselves. It is reasonable to assume that the next generation of gas separation membrane polymers will be even more resistant to plasticization than polysulfone, and cellulose acetate, so the assumption of constancy of these transport parameters will be even more firmly justified. 

The chemical stability of hydrogen separation membranes is a critical issue, because they will operate at elevated temperatures and pressures in atmospheres containing CO, CO2, and HjS, among other constituents. Figure 6.4 shows the hydrogen... 

Concentrate the CO2 using membrane technology. Distill the retentate to remove the methane. Take the bottoms from the demethanizer and perform an azeotropic distillation to separate CO2 from C2 using a C4 extraction fluid. Treat theazaotrope overhead with a membrane distillation hybrid to remove the CO2. Now combine the various streams as shown in Fig. P-23b. 

Jordal K, Bredesen R, Kvamsdal HM, and Bolland O. Integration of H2-separating membrane technology in gas turbine processes for CO2 capture. Energy 2004 29 1269-1278. 

Meldon JH and Dutta A. Analysis of ultimate permselectivity for H2S over CO2 in alkaline solutions. Chem Eng Sci, 1994 49(5) 689-697. Saha S and Chakma A. Selective CO2 separation from CO2/C2H6 mixtures by immobilized diethanolamine/PEG membranes. J Mem... 

Feron PHM and Jansen AE. CO2 separation with polyolefin membrane contactors and dedicated absorption liquids Performances and prospects. Sep. Purif. Technol. 2002 27 231-242. 

Chen H, Ohuskovic G, Majumdar S, and Sirkar KK. Immobilized glycerol-based liquid membranes in hollow fibers for selective CO2 separation from CO2-N2 mixtures. J. Mem. Sci. 2001 183 75-88. 

Permeable gas separation membranes utilize differences in solubility and diffusion of different gas components in polymer materials. In recent years membrane-based technologies have gained increasing importance in gas processing. Typical applications are CO2 removal from natural gas or hydrogen recovery from synthesis gas. The degree of selectivity between different gas components depends on the membrane used so that it is necessary to contact the manufacturers for a concrete project. Membrane separation units are usually supplied skid mounted. 

Membrane-based separation processes to capture either H2 or CO2 from the gasifier are new and less studied methods of CO2 separation and capture. Membranes separate the desired gas component without requiring phase changes or chemical or physical sorption. The cost of membrane separation is generally dictated by the overall pressure drop. Membranes made of various types of materials such as polymers, metals, and rubber composites have been investigated. Palladium and molecular sieves are currently under study. ° ... 

SILP systems have proven to be interesting not only for catalysis but also in separation technologies [128]. In particular, the use of supported ionic liquids can facilitate selective transport of substrates across membranes. Supported liquid membranes (SLMs) have the advantage of liquid phase diffusivities, which are higher than those observed in polymers and grant proportionally higher permeabilities. The use of a supported ionic liquid, due to their stability and negligible vapor pressure, allow us to overcome the lack of stability caused by volatilization of the transport liquid. SLMs have been applied, for example, in the selective separation of aromatic hydrocarbons [129] and CO2 separation [130, 131]. 

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