Carbon dioxide separation membrane systems

Carbon Dioxide Separation Membrane Systems CO2 Captnre from Flue Gases... 

Zhou, J., et al. (2006). Molecular Dynamics Simulation ofDiffusion of Gases in Pure and Silica-FilledPoly (l-trimethylsilyl-l-propyne)fPTMSP]. Polymer, 47(14), 5206-5212. Scholes, C. A., Kentish, S. E. Stevens, G. W. (2008). Carbon Dioxide Separation Through Polymeric Membrane Systems for Flue Gas Applications. Recent Patents on Chemical Engineering, 1(1), 52-66. 

Scholes, C. A. Kentish, S. E. and Stevens, G. W. Carbon Dioxide Separation Through Polymeric Membrane Systems for flue Gas Applications RecaUXcUa ClKm Er. 2008,1(1), 52-66. 

Adsorption systems employing molecular sieves are available for feed gases having low acid gas concentrations. Another option is based on the use of polymeric, semipermeable membranes which rely on the higher solubiHties and diffusion rates of carbon dioxide and hydrogen sulfide in the polymeric material relative to methane for membrane selectivity and separation of the various constituents. Membrane units have been designed that are effective at small and medium flow rates for the bulk removal of carbon dioxide. 

FoUowiag Monsanto s success, several companies produced membrane systems to treat natural gas streams, particularly the separation of carbon dioxide from methane. The goal is to produce a stream containing less than 2% carbon dioxide to be sent to the national pipeline and a permeate enriched ia carbon dioxide to be flared or reinjected into the ground. CeUulose acetate is the most widely used membrane material for this separation, but because its carbon dioxide—methane selectivity is only 15—20, two-stage systems are often required to achieve a sufficient separation. The membrane process is generally best suited to relatively small streams, but the economics have slowly improved over the years and more than 100 natural gas treatment plants have been installed. 

In principle, the combination of membranes for bulk removal of the carbon dioxide with amine units as polishing systems offers a low-cost alternative to all-amine plants for many streams. However, this approach has not been generally used because the savings in capital cost are largely offset by the increased complexity of the plant, which now contains two separation processes. The one exception has been in carbon dioxide flood enhanced oil-recovery projects [49,54], in which carbon dioxide is injected into an oil formation to lower the viscosity of the oil. Water, oil and gas are removed from the formation the carbon dioxide is separated from the gas produced and reinjected. In these projects,... 

An emulsion liquid membrane (ELM) system has been studied for the selective separation of metals. This system is a multiple phase emulsion, water-in-oil-in-water (W/O/W) emulsion. In this system, the metal ions in the external water are moved into the internal water phase, as shown in Fig. 3.4. The property of the ELM system is useful to prepare size-controlled aiKl morphology controlled fine particles such as metals, carbonates/ and oxalates.Rare earth oxalate particles have been prepared using this system, consisting of Span83 (sorbitan sesquioleate) as a surfactant and EHPNA (2-ethyl-hexylphospholic acid mono-2-ethylhexyl ester) as an extractant. In the case of cerium, well-defined and spherical oxalate particles, 20 - 60 nm in size, are obtained. The control of the particle size is feasible by the control of the feed rare earth metal concentration and the size of the internal droplets. Formation of ceria particles are attained by calcination of the oxalate particles at 1073 K, though it brings about some construction of the particles probably caused by carbon dioxide elimination. 

It may be added, however, that membrane systems have been used successfully to separate carbon dioxide from natural gas, notably in enhanced oil recovery operations. Here (supercritical) carbon dioxide is injected into a petroleum-bearing formation where the carbon dioxide acts to increase the oil mobility and its subsequent recovery. The carbon dioxide-rich gaseous effluent is recovered, and the carbon dioxide concentrated and re-injected. 

Noyes G, A mobile liquid venting membrane separator for carbon dioxide, humidity, and waste heat removal from spacesuits and manned spacecraft. 23rd International Conference on Environmental Systems, Colorado Springs, CO, July 12-15, 1993. 

Technical tour to visit Research Institute of Innovation Technology for the Earth (RITE) was planned on one day morning during the period of the conference, and made a strong impression on the visitors. There are the first world demonstration plant for methanol synthesis from carbon dioxide and other related technologies such as membrane devices for separation of CO2 from the flue gas. The visitors could see also biochemical studies concerning CO2 fixation, and studies on total systems for CO2 mitigation. On the afternoon of the same day, they visited to Todai-ji temple located in the world famous ancient capital of... 

Through membrane reactor model calculations it has been shown that membranes can enhance the conversion of a WGS membrane reactor and concurrently separate hydrogen from carbon dioxide. This system can be used to control the release of CO2 to the atmosphere from a IGCC power plant. Through process... 

CA blend membranes for gas separation are commercially available from Envlrogenlcs Systems Co. (El Monte, CA), Separex Corp. (Anaheim, CA) and Grace Membrane Systems (Houston, TX), and are applied In spiral-wound modules for the separations of acidic gaseous components from natural gas, for the recovery of carbon dioxide In enhanced oil recovery processes for gas dehydration or the separation of hydrogen from carbon monoxide (21-23). 

Solvent-drying. After annealing at lOO C, the absorbed water inside the membranes was removed by a proprietary procedure. Its effect on gas permeation is given in Table VI. No effect is observed on the.helium and carbon dioxide permeability rates. But the permeability rates of nitrogen and methane are considerably lowered so that the separations of both systems, helium/nltrogen and carbon dloxlde/methane, are enhanced. With a value of 44.1 for helium/ nitrogen, the ideal separation factor of the external reference membrane is slightly exceeded, whereas the separation factor for CO2/CK of more than 2500 is Improved by a factor of 600. 

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