Separation and Capture of CO₂from Large Stationary Sources and Sequestration in Geological Formations—Coalbeds and Deep Saline Aquifers

Abstract

The topic of global warming as a result of increased atmospheric CO2 concentration is arguably the most important environmental issue that the world faces today. It is a global problem that will need to be solved on a global level. The link between anthropogenic emissions of CO2 with increased atmospheric CO2 levels and, in turn, with increased global temperatures has been well established and accepted by the world. International organizations such as the United Nations Framework Convention on Climate Change (UNFCCC) and the Intergovernmental Panel on Climate Change (IPCC) have been formed to address this issue. Three options are being explored to stabilize atmospheric levels of greenhouse gases (GHGs) and global temperatures without severely and negatively impacting standard of living: (1) increasing energy efficiency, (2) switching to less carbon-intensive sources of energy, and (3) carbon sequestration. To be successful, all three options must be used in concert. The third option is the subject of this review. Specifically, this review will cover the capture and geologic sequestration of CO2 generated from large point sources, namely fossil-fuel-fired power gasification plants. Sequestration of CO2 in geological formations is necessary to meet the President's Global Climate Change Initiative target of an 18% reduction in GHG intensity by 2012. Further, the best strategy to stabilize the atmospheric concentration of CO2 results from a multifaceted approach where sequestration of CO2 into geological formations is combined with increased efficiency in electric power generation and utilization, increased conservation, increased use of lower carbon-intensity fuels, and increased use of nuclear energy and renewables. This review covers the separation and capture of CO2 from both flue gas and fuel gas using wet scrubbing technologies, dry regenerable sorbents, membranes, cryogenics, pressure and temperature swing adsorption, and other advanced concepts. Existing commercial CO2 capture facilities at electric power-generating stations based on the use of monoethanolamine are described, as is the Rectisol process used by Dakota Gasification to separate and capture CO2 from a coal gasifier. Two technologies for storage of the captured CO2 are reviewed--sequestration in deep unmineable coalbeds with concomitant recovery of CH4 and sequestration in deep saline aquifers. Key issues for both of these techniques include estimating the potential storage capacity, the storage integrity, and the physical and chemical processes that are initiated by injecting CO2 underground. Recent studies using computer modeling as well as laboratory and field experimentation are presented here. In addition, several projects have been initiated in which CO2 is injected into a deep coal seam or saline aquifer. The current status of several such projects is discussed. Included is a commercial-scale project in which a million tons of CO2 are injected annually into an aquifer under the North Sea in Norway. The review makes the case that this can al...

Flue-Gas Carbon Capture on Carbonaceous Sorbents: Toward a Low-Cost Multifunctional Carbon Filter for “Green” Energy Producers

“…The amine absorption process shown in Figure 2 is known to be effective for separating CO 2 from mixtures of natural gas and flue gas, 3,27 and, hence, it is used in this work as a point of reference for alternative CO 2 separation processes. In this benchmark process, the feed is the Wyodak flue-gas mixture characterized in Table 1 and the solvent is a weakly basic aqueous monoethanolamine (MEA) solution.…”

“…All these absorption, adsorption, and membrane approaches have been well-documented (see, for example, the reported work of Herzog and Drake, 1 Mimura et al, 2 White et al, 3 and Aaron and Tsouris 4 ). The main directions of research aimed at future innovations are focused on developing novel CO 2 separation materials, such as ionic liquids, 5 ionic polymers, [6][7][8] and nanosilica and nanotube composites, [9][10][11] just to mention recent examples from our laboratory; however, this is an active field of research in many other laboratories.…”

Surface and Subsurface Geochemical Monitoring of an EOR-CO2Field: Buracica, Brazil

“…The average composition of Helium (He) is 0.4 ± 0.5 ppm, Neon (Ne) is 0.17 ± 0.17 ppm, Argon (Ar) is 224 ± 87 ppm and Krypton (Kr) is 0.79 ± 0.23 ppm. The isotopic composition of Ar displays an average 40 Ar/ 36 Ar ratio of 350 ± 10, while He has 3 He/ 4 He ratios of 7.8 × 10 -8 ± 3.7 × 10 -8 . This composition is highly exotic compared with other natural fluid reservoirs of the Earth's system such as the air, the crust, or the mantle.…”

“…The GV 5400 comprises a Faraday cup and an electron multiplier (Balzers SEM 217). These collectors are used alternately for the 3 He/ 4 He ratio analysis. The most abundant isotope ( 4 He) is measured on the Faraday cup, whereas 3 He is measured by the electron multiplier.…”

“…Carbon Capture and Storage (CCS) projects in geological depleted petroleum fields or deep saline aquifers [1][2][3][4] have been envisaged as solutions to mitigate increasing atmospheric CO 2 . The enhanced recovery of oil (EOR) based on the injection of CO 2 is an expanding technology that offers the advantage of limiting CO 2 emissions in addition to an increased oil production.…”