Polymeric Amine-Based Facilitated Transport Membranes for Post-Combustion Carbon Capture
Presented by NETL at North American Membrane Society, 06/18
Baker, James S.↗
Engineering topics
Hopkinson, David
Publications and source records attributed to Hopkinson, David.
Ionic cross-linked polyether and silica gel mixed matrix membranes for CO 2 separation from flue gas
Mixed matrix membranes (MMMs) were prepared by incorporating 10 wt%, 20 wt% and 30 wt% silica gel filler particles into novel ionic cross-linked polyether (IXPE) polymers. Porous silica gel has the advantage of high surface area that can increase the free volume and permeability in a polymer film while also being commercially available and low cost. The MMMs featured high chemical and thermal stability as well as a modest improvement in storage modulus. These features are due to the excellent interfacial interaction between silica gel filler particles and the polymer matrix. Increasing the loading of silica gel particles in MMMs resulted in higher permeability up to 120 Barrer for CO 2 , which is about 40% higher than the neat polymer matrix. Finally, most importantly, the MMMs maintained a very high CO 2 /N 2 selectivity performance of around 41 for all particle loadings that were tested.
36 MATERIALS SCIENCE↗
An automated lab-scale flue gas permeation membrane testing system at the National Carbon Capture Center
A constant pressure, mixed gas permeation testing skid was deployed at the National Carbon Capture Center to test membrane performance when continuously exposed to slipstream post-combustion flue gas. Small, laboratory scale membranes can be loaded for testing and the degree of automation allowed the skid to be run unattended for several weeks at a time. In this report, we share our experience in commissioning the skid and quantifying CO 2 , N 2 and O 2 permeances of several membranes during the first round of testing. Dense films of polydimethylsiloxane and poly(bistrifluoroethoxyphosphazene) were tested with flue gas for approximately 20 h each. Here, in addition, we successfully tested four thin film composite hollow fiber membranes made by a dip coating process, consisting of porous Torlon hollow fibers coated with a selective layer of poly(bistrifluoroethoxyphosphazene) or its mixed matrix with a metal organic framework SIFSIX-Cu-2i filler particles. Initial results suggest the polydimethylsiloxane showed comparable results to the literature data, but the coated hollow fiber membranes have lower CO 2 permeances relative to N 2 or O 2 permeances compared to their performance under idealized, dry, contaminant-free mixed gas conditions. While quantification of H 2 O permeance was performed, we found it was affected by concentration polarization even with small membrane area and a low stage cut.
47 OTHER INSTRUMENTATION↗
Active Response of Six-Coordinate Cu 2+ on CO 2 Uptake in Cu(dpa) 2 SiF 6 - i from in Situ X-ray Absorption Spectroscopy
Interpenetrated metal organic framework (MOF) Cu(dpa) 2 SiF 6 -i (dpa = dipyridyl acetylene) with 6-coordinate copper takes up CO 2 with isosteric heat of sorption Qst ≅ 40 kJ/mol, comparable to MOFs designed to have specific, strong chemisorption interactions. Although small pore size contributes to this high Qst, any preferred microscopic physisorption mechanisms were incompletely understood. We present in situ X-ray absorption spectroscopy results sensitive to local electronic structure around copper, fluorine, and nitrogen to look for signatures of CO 2 interaction with and near ionic species in Cu(dpa) 2 SiF 6 -i. No changes in F or N K edge spectra imply no structural or electronic distortions to SiF62– or dpa molecules on CO 2 uptake. Cu L 2,3 edge spectra confirm Cu 2+ valence and show weak systematic CO 2 -induced effects that result from distortions of the copper coordination shell. Finally, we suggest that electrostatic interaction between Cu 2+ and axially aligned CO 2 quadrupole moments contributes to the large Qst.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Evaluating the energy performance of a hybrid membrane-solvent process for flue gas carbon dioxide capture
In this study, a particularly energy intensive step in the conventional amine absorption process to remove carbon dioxide is solvent regeneration using a steam stripping column. An attractive alternative to reduce the energy requirement is gas pressurized stripping, in which a high pressure noncondensable gas is used to strip CO 2 off the rich solvent stream. The gas pressurized stripping column product, having CO 2 at high concentration and high partial pressure, can then be regenerated readily using membrane separation. In this study, we performed an energetic analysis in the form of total equivalent work and found that, for capturing CO 2 from flue gas, this hybrid stripping process consumes 49% less energy compared to the base case conventional MEA absorption/steam stripping process. We also found the amount of membrane required in this process is much less than required for direct CO 2 capture from the flue gas: approximately 100-fold less than a previously published two-stage cross-flow scheme, mostly due to the more favorable pressure ratio and CO 2 concentration. There does exist a trade-off between energy consumption and required membrane area that is most strongly affected by the gas pressurized stripper operating pressure. While initial analysis looks promising from both an energy requirement and membrane unit capital cost, the viability of this hybrid process depends on the availability of advanced, next generation gas separation membranes to perform the stripping gas regeneration.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Failure Mechanisms of Hollow Fiber Supported Ionic Liquid Membranes
Hollow fiber supported ionic liquid membranes (SILMs) were tested using the bubble point method to investigate potential failure modes, including the maximum transmembrane pressure before loss of the ionic liquid from the support. Porous hollow fiber supports were fabricated with different pore morphologies using Matrimid® and Torlon® as the polymeric material and 1-hexyl-3-methylimidalzolium bis(trifluoromethylsulfonyl)imide ([C6mim][Tf2N]) as the ionic liquid (IL) component. Hollow fiber SILMs were tested for their maximum pressure before failure, with pressure applied either from the bore side or shell side. It was found that the membranes exhibited one or more of three different modes of failure when pressurized: liquid loss (occurring at the bubble point), rupture, and collapse.
rupture↗
Phase change amino acid salt separates into CO2-rich and CO2-lean phases upon interacting with CO2
Not Available
Wang, Xianfeng↗
Verification of a solvent optimization approach for postcombustion CO 2 capture using commercial alkanolamines
This work verified a phase equilibrium approach for optimization of conceptual solvents by using process simulations of commercial solvents N-methyl-diethanolamine (MDEA) and 2-amino-2-methyl-1-propanol (AMP) aqueous solution, for a conventional absorption/desorption based postcombustion CO 2 capture process. The simulated total heat/total equivalent work for the investigated tertiary/hindered amines has the same trends as those based on the phase equilibrium approach for conceptual solvents with the same heat of reactions. Moreover, the simulated CO 2 working capacities for the commercial solvents agree well with those obtained with the phase equilibrium approach for the corresponding conceptual solvents, verifying the phase equilibrium approach. Finally, results of parametric tests using the AMP aqueous solution illustrate that there is an optimal lean loading for the lean solution and an optimal temperature for the stripper inlet solvent to achieve the least total equivalent work/total heat.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗