Carbon-dioxide separation

Carbon dioxide is produced by different industrial processes reported below  

Zeolite membranes with different topology were studied for CO2 separation from light gases. Table 17.5 reports some of the different results present in the open literature about CO2/N2 and CO2/CH4 separations. 

Flue gas from fossil fuel power generation is the single greatest contribution to CO2 emissions. Therefore, the separation and capture of CO2 from flue gas is one of the most important measures to control greenhouse gas emission. Generally, the flue gas from power plants has a large volume and a relatively 

Zeolite type-support T rc) CO 2 permeance (nmol m s Pa ) CO2IN2 CO2ICH4 Reference  

The effect of different counter-ions (K, Rb and Cs) in the supported NaY zeolite membranes on CO2/N2 separations has also been studied. For an equimolar mixture the selectivity is increased in the order Rb K Cs Na due to an increase of CO2/N2 sorption selectivity. In Table 17.6 the sorption, diffusion and overall permeation selectivity are reported for ion exchanged membranes.The sorption selectivity always increased for single and binary systems, however, the increase is very pronounced with the binary system and a zeolite membrane loaded with Rb ions shows the highest selectivity. 

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. 

Theoretical calculations indicated that in the absence of a gutter layer, the upper layer could achieve a CO2 permeance of over 3000 GPU with a CO2/N2 selectivity of 22. These results represent a significant increase in the gas permeance (72). 

Polymeric membranes have been investigated as a method to effectively separate CO2 from light gases, such as N2 and CH4 (73-75). 

With increasing improvements in membrane technologies, they offer an attractive alternative to existing solvent technologies for CO2 separation since they have several advantages, including potentially lower operating costs, environmental friendliness, a smaller footprint and ease of operation. 

However, for processes such as postcombustion removal of CO2 from the flue gases of coal-fired power stations, improvements in membrane performance are required to make them economically viable (76). 

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Hence, water, ammonia, hydrogen fluoride and carbon dioxide separate from the mixture into the gaseous phase. However, despite the possibility of a solid-state interaction, the application of ammonium acetate solutions for washing of... 

Ammonia, hydrogen fluoride and carbon dioxide separate from the system in the form of gaseous components. 

Carbon Dioxide Separation for Fuel Reforming Carbon dioxide separation reforming in the above mentioned is one of useful methodologies for efficient hydrogen production [29]. Calcium oxide (CaO) carbonation can absorb CO2 from the reformed gas and fix it. 

Han, C. and D.P Harrison, Simultaneous shift reaction and carbon dioxide separation for the direct production of hydrogen, Chem. Eng. Sci., 49, 5975-5883,1994. 

Chung, S.J. et al., Dual-phase inorganic metal-carbonate membrane for high temperature carbon dioxide separation, Ind. Eng. Chem. Res., 44, 7999, 2005. 

Gopalan AS, Wai CM, Jacobs HK, eds. Supercritical Carbon Dioxide Separations and Processes. Washington, DC American Chemical Society 2003. 

D. Parro, Membrane Carbon Dioxide Separation, Energy Prog. 5, 51 (1985). 

Parro, D. (1984) Membrane carbon dioxide separation proves out at Sacroc tertiary recovery project. Oil Gas Journal, 82 (39), 85-86, 88. 

Properties of Membranes for Hydrogen, Oxygen, and Carbon Dioxide Separation... 

Membranes are growing significantly also in gas separation, for example, the current market size of carbon-dioxide separation from natural gas is more than 70 million Euro/year. 

Netherlands Energy Research Foundation Combined Cycle Project - IGCC with C02 Removal Project Area - An Attractive Option for C02 Control in IGCC Systems Water Gas Shift with Integrated Hydrogen/Carbon Dioxide Separation (WIHYS) Process - Phase 1 Proof of Principle Alderliesten, P. T. and Bracht, M., eds. Contract JOU2-CT92-0158, Final Report (1995). 

Gamse, T., Marr, R., Froschl, F., and Siebenhofer, M., Extraction of furfural with carbon dioxide. Separation Sci Technol 1997, 32 (1-4), 355-371. 

Hydrogen and Carbon Dioxide Production from Steam-Methane Reformer Off Gas Production of Ammonia Synthesis Gas Hydrogen Recovery fiom Refinery Off Gases Methane-Carbon Dioxide Separation from Landfill Gas... 

Tetrakis(triphenylphosphine)platinum(0) is a pale yellow powder which decomposes in the air to a red liquid at 118-120° and melts in vacuo (1 mm.) to a yellow liquid at 159-160°. The infrared spectrum in Nujol show s absorption maxima at 700(vs), 737(vs), 837(w), 992(s), 1022(s), 1077(vs), 1147(m), 1162(m), 1302(w), and 1432(vs) cm. h The compound is soluble in benzene with dissociation by leaving the benzene solution in the air, a white pow der [the carbonatobis(triphenylphosphine)-platinum(II) formed by action of oxygen and carbon dioxide] separates slowly. The compound reacts wdth carbon tetrachloride, giving cfs-dichlorobis(triphenylphosphine)platinum(II). ... 

Hirayama Y et al. Novel membranes for carbon dioxide separation. Energy Conv. Mgmt. 1995 36(6-9) 435 38. 

Carbon dioxide separation from the air, mixtures with CH4, N2, O2, has been studied from both biological and engineering applications. Spiral-type FLM, HFLM, and capillary membrane techniques were tested for these purposes. 

Carbon dioxide separation from nitrogen using Y-type zeolite membranes... 

Gupta, H. and Fan, LS. Carbonation-calcination cycle using high reactivity calcium oxide for carbon dioxide separation from flue gas. Industrial Engineering Chemistry Research, 2002, 41, 4035-4042. 

Physical sorbents for carbon dioxide separation and removal were extensively studied by industrial gas companies. Zeolite 13X, activated alumina, and their improved versions are typically used for removing carbon dioxide and moisture from air in either a TSA or a PSA process. The sorption temperatures for these applications are usually close to ambient temperature. There are a few studies on adsorption of carbon dioxide at high temperatures. The carbon dioxide adsorption isotherms on two commercial sorbents hydrotalcite-like compounds, EXM911 and activated alumina made by LaRoche Industries, are displayed in Fig. 8.F23,i24] shown in Fig. 8, LaRoche activated alumina has a higher carbon dioxide capacity than the EXM911 at 300° C. However, the adsorption capacities on both sorbents are too low for any practical applications in carbon dioxide sorption at high temperature. Conventional physical sorbents are basically not effective for carbon dioxide capture at flue gas temperature (> 400°C). There is a need to develop effective sorbents that can adsorb carbon dioxide at flue gas temperature to significantly reduce the gas volume to be treated for carbon sequestration. 

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