Carbon capture selectivity

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. 

Table 8.3 summarizes fuel costs, in cents per mile driven, for the various vehicle types. These results use the default values in H2Sim, including the assumption of low hydrogen production and short distance. These costs do not include any carbon capture and sequestration. Depending on the distribution option selected, the estimated fuel costs... 

Baneijee, R. et al.. Control of pore size and functionality in isoreticular zeolitic im-idazolate frameworks and their carbon dioxide selective capture properties. J. Am. Chem. Soc. 2009,131(11), 3875-3877. 

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. 

Solubility of CO2 in aqueous amine solutions a study to select solvents for carbon capture from natural-gas power plant... 

The same approach can be applied to carbon capture from low pressure gas streams as can be found in the flue gasses from power plants, refineries, and selected streams from e g. the steel indnstry. 

Gas testing of these membranes for carbon capture applications showed an enhanced CO2 permeance up to 1830 GPU, without a significant drop in CO2/N2 selectivity at 35°C and 350 kPa, relative to a pure PEBAX upper layer. The impacts of temperature and pressiue on membrane performance were investigated for temperatures from 25°C to 55°C and pressures from 100 kPa to 500 kPa. 

Second, what will be the energy requirement of the process when the previous conditions are fulfilled The energy challenge, one of the most stringent selection criteria of carbon capture processes has to be stressed here. 

This characteristic will govern, to a large extent, the operating expenses (OPEX) of the process. Standard post-combustion capture processes, such as gas liquid absorption in a chemical solvent (MEA), typically require 3.5 GJ (thermal basis) per ton of recovered CO2, and 2 GJ ton is often considered as a target. The importance of energy requirement considerations in the carbon capture process selection results from the secondary CO2 emissions which are generated by the capture process. Figure 2.5 summarizes the interplay between CO2 emissions by the reference plant and secondary, additional CO2 emissions due to the capture step. 

The identification of the minimal effective selectivity which enables the target separation performances to be attained is often one of the first problems to be solved in the design of membrane processes. For the post-combustion carbon capture challenge, the minimal selectivity can be determined for the set of process performances to be attained a capture ratio, R, of 0.8 (or more) and a permeate purity, j, of 0.8 (or more). Based on the assumptions detailed in the... 

In liquid separation, hollow fiber membranes based on PBI have shown excellent performance for pervaporation dehydration of organic liquids. For example, a dual layer PEI-PBI hollow fiber membrane with an outer selective layer of PBI showed better performance than most other polymeric membranes in pervaporation dehydration of ethylene glycol. Sulfonation modifications of PBI membranes have demonstrated excellent separation efficacies in the dehydration of acetic acid. Studies have shown that PBI hollow fiber membranes were effective in separating chromates from solutions. Also, PBI nanofiltration hollow fiber membranes are promising candidates as forward osmosis membranes. In gas separation, recent studies sponsored by the Department of Energy at Los Alamos National Laboratories and SRI International demonstrated potential applications of PBI membranes in carbon capture and Hj purification from synthesis gas streams at elevated temperatures. H2/CO2 selectivity > 40 has been achieved at H2 permeability of 200 GPU at 250°C. ... 

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