Tải bản đầy đủ - 0trang
4 CO[sub(2)] Reuse towards Low Carbon Economy
CARBON CAPTURE AND STORAGE
ves, or in aqu
uifers), or as industrial feedstock foor synthesis of chemicalls
(Omaee 2006). Tech
hnological ooptions for C
CO2 capture from diluted
streaams consistss of chemiccal solventss (e.g., aminnes, potassiium carbonate, aqueouus
monia); physical solvents (e.g., glyccol, methanool, ionic liquuids); chem
dified sorbents, metalorrganic frameeworks); meembranes (e.g., polymerr,
matic processses; novel methods
(e.g., CO2 hydraates) (Arestaa et al. 2010)).
Thesse technologiies are discu
ussed in detaail in other chhapters of thhis book.
Tablle 7.2. Catio
mprising the main types of ionic liquuids (adapted
m Zhang et all. 2006)
I−, Brr−, Cl−
ZnCl3−, CuuCl2−, SnCl3−
ure 7.4. Enerrgy productio
on intended for low carbbon economyy
CARBON CAPTURE AND STORAGE
7.4.2 Risks of CCS
Despite diverse technological advancements in CCS, the major challenges for
global implementation of CCS are: (i) significant investment cost for infrastructure; (ii)
lack of comprehensive understanding of the risk factors associated with the long-term
ecological consequences of CCS via existing technologies; and (iii) risk factors of the
reservoir options (Liu and Gallagher 2010). CO2 storage in deep geological formations
and ocean is actively debated in the literature, due to seemingly plausible risks of
adverse impact on the aquatic environment (i.e., ocean acidification, an effect on marine
life and eco-balance, etc.) (Zevenhoven et al. 2006). Moreover, on a long-term basis
these solutions are temporary. For example, disposal/storage in deep geological
formations seems to be a less expensive and risky option than ocean sequestration,
however, any accidental leakage of CO2 can lead to leaching of harmful trace elements
in freshwater aquifers by lowering of pH and can also adversely affect soil chemistry. It
was estimated that even 1% leak of captured CO2 could nullify the sequestration effort
in a century and could be catastrophic for humans and animals (Liu and Gallagher
2010). The CO2 leakage happened in the Lake Nahos in Africa asphyxiated about three
thousand people (Muradov and Veziroglu 2008). Thus, the low carbon economy concept
has immense challenges due to lack of reliability of existing CCS technologies.
7.4.3 Production of Carbon Free or Carbon Neutral Fuels
Another prospective decarbonisation strategy for low carbon economy could be
the production of hydrogen from fossil fuels (e.g., natural gas, petroleum or coal)
coupled with CO2 sequestration. In this approach, hydrogen is produced from fossil fuel
and the CO2 formed as a reaction by-product is captured and sequestered. The energy
conversion efficiency for coal and natural gas as a feed for the production of hydrogen
are 50‒60% and 70‒75%, respectively (Muradov and Veziroglu 2008). The
commendable features of this approach are that the energy infrastructure could be based
on a range of carbonaceous fuels, either biomass or fossil based, without the pollution
load of CO2 in the atmosphere. Similarly, the technologies under active research and
development such as steam methane reforming can play a major role in driving low
carbon economies. Strategies for achieving the goal of low carbon economy at the
utilization level of fuels/energy are also important (Damm and Fedorov 2008). Use of
electric vehicles, hydrogen powered vehicles, and substitution of petroleum fuels with
carbon neutral biofuels are few examples discussed in the following.
Electric Vehicles. Electric vehicles are attractive mode to eliminate direct
carbon emissions by the transportation sector. The electricity consumed by the electric
vehicles can be generated at a large-scale centralized location from renewable/
alternative energy sources or from fossil fuels coupled with CO2 sequestration. This
electric energy will be used by the vehicle to produce mechanical energy with no direct
CARBON CAPTURE AND STORAGE
CO2 emissions. Fig. 7.5 sh
hows the geeneral schem
me for low carbon ecoonomy at thhe
utilizzation level of fuels/enerrgy. The eneergy efficienncy of electrric vehicles can be betteer
than internal com
mbustion engines. Curreently, howevver, energy ddensity and the chargingg
time of batteries are limiting factors (Dam
mm and Feddorov 2008).. Use of raree earth metalls
(e.g.,, lithium) in
n batteries are
a also a matter
of conncern as theey may ham
mper the cosst
petitiveness of electric vehicles.
ure 7.5. Straategies for acchieving thee goal of low
w carbon ecconomy at thhe utilizationn
levell of fuels/eneergy
Hydrogeen Fueled Vehicles.
Use of hydroggen in autom
mobiles can provide zero
n in two waays: fuel cell technologgy and interrnal combusstion enginee.
Simiilar to electrricity, the pu
ure hydrogeen can be prroduced at a central loccation (usingg
gy sources or
o from fossil fuels cooupled with CO2 sequestration) andd
ugh infrastruucture (refueelling stationns, pipeliness, trucking, etc.) tailoredd
hydrogeen can be burned in an internall combustioon engine oor
d to electricitty via a fue l cell system
m (Fig. 7.5). Analysis oof
severral feasible scenarios
suuggests that the
t broad sccale use of hhydrogen-fueelled vehiclees
the atmosphericc levels of CO2 (Dutton aand Page 20007; Conte 2009; Cormoos
et al. 2010). Nevertheless
, multiple techno-econnomic barriiers such as
hydrogen storagee, infrastructture investm
ment and safeety must be aaddressed.
Carbon Neutral Bioofuels. It is an alternativve pathway that employys the use of
modiified internaal combustion
n engine. Biiofuels can bbe carbon neeutral or evenn negative, iif
they are produceed from biom
mass using renewable/al
lternative noon-fossil eneergy sourcess.
CARBON CAPTURE AND STORAGE
Carbon neutral biofuels have huge potential in achieving the goal of low carbon
economy as in most cases; carbon neutral biofuels can simply replace fossil fuels
without major changes to the infrastructure (Omae 2006; Aresta et al. 2010).
Nevertheless, the implementation of carbon neutral biofuels will require major initiatives
and intensives from the governments.
The planet earth cannot restore the imbalance caused by anthropogenic activities
such as growing release of CO2 in the atmosphere via use of fossil fuels. If the carbon
emission is not mitigated or neutralized in time, the adverse effects of global warming
due to higher level of GHGs can be severe. Fortunately, the current momentum of
research/development and initiations taken by international community is a positive note
in the direction of restoration of the environment. Several novel as well as wellestablished technologies for CCS are gradually becoming mainstream pathways for
fighting climate change.
Utilization of CO2 for the production of synthetic fuels, chemical feedstock,
polymers, and polycarbonates are some exemplary steps. CO2 has been successfully
transformed into methanol, synthesis gas, and synthetic hydrocarbon fuels to compete
with petroleum products. On the other hand, CO2 also has great potential as a feedstock
for industrially important chemicals such as formic acid, formic acid esters, formamides,
other hydrogenation products, carbonic acid esters, carbamic acid esters (urethanes),
lactones, carboxylic acids. Developments in polymer science have paved way for
fixation of CO2 as commercial polymeric materials. The thermodynamic stability of CO2
requires efficient metal catalysts to achieve economically feasible conversion processes.
The recent literature is full of novel catalyst systems for CO2 transformation, thereby,
proving the potential of future use of CO2.
Low carbon economy is based on CCS and sustainable energy production
technologies. International community is in unison of need for low carbon global
economy and taking all possible steps to achieve this goal. Therefore, nowadays, low
carbon uses are also considered to measure modernization and development of any
nation. However, risks associated with carbon capture and sequestration in deep ocean,
geological formations are significant and pose challenge to the implementation of low
carbon economy on a global basis. Utilization of diversified alternative energy resources
such as biofuels, solar, wind, tidal, nuclear, geothermal could provide more feasible
ways of mitigating carbon emission as well as energy security for the future generations.
CARBON CAPTURE AND STORAGE
Agnolucci, P., Ekins, P., Iacopini, G., Anderson, K., Bows, A., Mander, S., and
Shackley, S. (2009). "Different scenarios for achieving radical reduction in
carbon emissions: A decomposition analysis." Ecological Economics, 68(6),
Andrew, J., Kaidonis, M.A., and Andrew, B. (2010). "Carbon tax: Challenging
neoliberal solutions to climate change." Critical Perspectives on Accounting,
Aouissi, A., Al-Deyab, S.S., Al-Owais, A., and Al-Amro, A. (2010). "Reactivity of
Heteropolytungstate and Heteropolymolybdate Metal Transition Salts in the
Synthesis of Dimethyl Carbonate from Methanol and CO2." International
Journal of Molecular Sciences, 11(7), 2770‒2779.
Aresta, M., Quaranta, E., and Tommasi, I. (2010). "Prospects for the utilization of
carbon dioxide." Energy Conversion and Management, 33(5‒8), 495‒504.
Baba, A., Kashiwagi, H., and Matsuda, H. (1987). ‘‘Reaction of carbon dioxide with
oxetane catalyzed by organotin halide complexes: control of reaction by
ligands.’’ Organometallics, 6, 137–140.
Bai, D., Jing, H., Liu, Q., Zhu, Q., and Zhao, X. (2009). "Titanocene dichloride-Lewis
base: An efficient catalytic system for coupling of epoxides and carbon dioxide."
Catalysis Communications, 11(3), 155–157.
Bennaceur, K., and Gielen, D. (2010) "Energy technology modelling of major carbon
abatement options." International Journal of Greenhouse Gas Control, 4(2),
Conte, M. (2009). "ENERGY | Hydrogen Economy." Encyclopedia of Electrochemical
Power Sources, Elsevier, Amsterdam, 232–254.
Cormos, C.-C., Starr, F., and Tzimas, E. (2010). "Use of lower grade coals in IGCC
plants with carbon capture for the co-production of hydrogen and electricity."
International Journal of Hydrogen Energy, 35(2), 556–567.
Damm, D.L., and Fedorov, A.G. (2008). "Conceptual study of distributed CO2 capture
and the sustainable carbon economy." Energy Conversion and Management,
Darensbourg, D.J., and Holtcamp, M.W. (1996). "Catalysts for the reactions of epoxides
and carbon dioxide." Coordination Chemistry Reviews, 153, 155–174.
Darensbourg, D.J., Rodgers, J.L., Mackiewicz, R.M., and Phelps, A.L. (2004). "Probing
the mechanistic aspects of the chromium salen catalyzed carbon dioxide/epoxide
copolymerization process using in situ ATR/FTIR." Catalysis Today, 98(4), 485–
Du, Y., Kong, D.-L., Wang, H.-Y., Cai, F., Tian, J.-S., Wang, J.-Q., and He, L.-N.
(2005). "Sn-catalyzed synthesis of propylene carbonate from propylene glycol
and CO2 under supercritical conditions." Journal of Molecular Catalysis A:
Chemical, 241(1–2), 233–237.
CARBON CAPTURE AND STORAGE
Dutton, A.G., and Page, M. (2007). "The THESIS model: An assessment tool for
transport and energy provision in the hydrogen economy." International Journal
of Hydrogen Energy, 32(12), 1638–1654.
Halloran, J.W. (2007). "Carbon-neutral economy with fossil fuel-based hydrogen energy
and carbon materials." Energy Policy, 35(10), 4839–4846.
Halmann, M.M. (1993). Chemical fixation of carbon dioxide: Methods for recycling
CO2 into useful products. Boca Raton, FL: CRC Press.
Hamilton, M.R., Herzog, H.J., and Parsons, J.E. (2009). "Cost and U.S. public policy for
new coal power plants with carbon capture and sequestration." Energy Procedia,
Hawkins, A.S., McTernan, P.M., Lian, H., Kelly, R.M., and Adams, M.W.W. (2013).
“Biological conversion of carbon dioxide and hydrogen into liquid fuels and
industrial chemicals.” Current Opinion in Biotechnology, 24(3), 376‒384.
Herzog, H., and Golomb, D. (2004). “Carbon Capture and Storage from Fossil Fuel
Use.” Contribution to Encyclopedia of Energy. Available online:
http://sequestration.mit .edu/pdf/enclyclopedia_of_energy_article.pdf (accessed
Herzog, H., Drake, E., and Adams, E. (1997). CO2 Capture, Reuse, and Storage
Technologies for Mitigating Global Climate Change. A White Paper Final
Report. Energy Laboratory. Massachusetts Institute of Technology Available on
Hickman, R., Ashiru, O., and Banister, D. (2010). "Transport and climate change:
Simulating the options for carbon reduction in London." Transport Policy, 17(2),
Hsu, T.-J., and Tan, C.-S. (2002). "Block copolymerization of carbon dioxide with
cyclohexene oxide and 4-vinyl-1-cyclohexene-1,2-epoxide in based
poly(propylene carbonate) by yttrium-metal coordination catalyst." Polymer,
Hwang, J.S., Chang, J.S., Park, S.E., Ikeue, K., and Anpo, M. (2005). “Photoreduction
of carbondioxide on surface functionalized nanoporous catalysts.” Top. Catal.
Indrakanti, V.P., Kubicki, J.D., and Schobert, H.H. (2009). “Photoinduced activation of
CO2 on Ti-based heterogeneous catalysts: Current state, chemical physics-based
insights and outlook.” Energy Environ. Sci., 2, 745–758.
Inoue, S., Koinuma, H., and Tsuruta, T. (1969). “Copolymerization of carbon dioxide
and epoxide.” J. Polym. Sci. Polym. Lett., 7, 287–292.
Inoue, T., Fujishima, A., Konishi, S., and Honda, K. (1979). Photoelectrocatalytic
reduction of carbon dioxide in aqueous suspensions of semiconductor powders.
Nature, 277, 637–638.
Jiang, Z., Xiao, T., Kuznetsov, V.L., and Edwards, P.P. (2010). “Turning carbon dioxide
into fuel.” Phil.Trans. R. Soci. A, 368, 3343‒3364.
CARBON CAPTURE AND STORAGE
Kannan, R. (2009). "Uncertainties in key low carbon power generation technologies–
Implication for UK decarbonisation targets." Applied Energy, 86(10), 1873–
Liu, B., Zhao, X., Guo, H., Gao, Y., Yang, M., and Wang, X. (2009). "Alternating
copolymerization of carbon dioxide and propylene oxide by single-component
cobalt salen complexes with various axial group." Polymer, 50(21), 5071–5075.
Liu, H., and Gallagher, K.S. (2010). "Catalyzing strategic transformation to a lowcarbon economy: A CCS roadmap for China." Energy Policy, 38(1), 59–74.
Liu, Y., Huang, K., Peng, D., and Wu, H. (2006). "Synthesis, characterization and
hydrolysis of an aliphatic polycarbonate by terpolymerization of carbon dioxide,
propylene oxide and maleic anhydride." Polymer, 47(26), 8453–8461.
Louitzenhiser, P.G., Meier A., and Steinfeld, A. (2010)."Review of the two-step
H2O/CO2-splitting solar thermochemical cycle based on Zn/ZnO redox
reactions." Materials, 3, 4922‒4938.
Lu, X.-B., Zhang, Y.-J., Jin, K., Luo, L.-M., and Wang, H. (2004). "Highly active
electrophile-nucleophile catalyst system for the cycloaddition of CO2 to epoxides
at ambient temperature." Journal of Catalysis, 227(2), 537–541.
Ma, J., Sun, N., Zhang, X., Zhao, N., Xiao, F., Wei, W., and Sun, Y. (2009). "A short
review of catalysis for CO2 conversion." Catalysis Today, 148(3–4), 221–231.
Muradov, N.Z., and Veziroglu, T.N. (2008). "Green" path from fossil-based to hydrogen
economy: An overview of carbon-neutral technologies." International Journal of
Hydrogen Energy, 33(23), 6804–6839.
Nader, S. (2009). "Paths to a low-carbon economy‒The Masdar example." Energy
Procedia, 1(1), 3951–3958.
Ockwell, D.G., Watson, J., MacKerron, G., Pal, P., and Yamin, F. (2008). "Key policy
considerations for facilitating low carbon technology transfer to developing
countries." Energy Policy, 36(11), 4104–4115.
Olah, G.A., Prakash, G.K.S., and Goeppert, A. (2011). “Anthropogenic chemical carbon
cycle for a sustainable future.” Journal of the American Chemical Society, 133
Omae, I. (2006). "Aspects of carbon dioxide utilization." Catalysis Today, 115(1–4), 33–
Paddock, R.L., Hiyama, Y., McKay, J.M., and Nguyen, S.T. (2004). "Co(III)
porphyrin/DMAP: an efficient catalyst system for the synthesis of cyclic
carbonates from CO2 and epoxides." Tetrahedron Letters, 45(9), 2023–2026.
Palgunadi, J., Kwon, O.S., Lee, H., Bae, J.Y., Ahn, B.S., Min, N.-Y., and Kim, H.S.
(2004). "Ionic liquid-derived zinc tetrahalide complexes: structure and
application to the coupling reactions of alkylene oxides and CO2." Catalysis
Today, 98(4), 511–514.
Parsons Brinckerhoff (PB) and Global CCS Institute (GCCSI) (2011). “Accelerating the
uptake of CCS: Industrial use of captured carbon dioxide.” Available at
CARBON CAPTURE AND STORAGE
http://www.globalccsinstitute.com/publications/accelerating-uptake-ccsindustrial-use-captured-carbon-dioxide (accessed July 2013).
Peace, J., and Juliani, T. (2009). "The coming carbon market and its impact on the
American economy." Policy and Society, 27(4), 305–316.
Rahimpour, M.R. (2007). “A two-stage catalyst bed concept for conversion of carbon
dioxide into methanol.” Fuel Processing Technology, 89, 556–566.
Richels, R.G., and Blanford, G.J. (2008). "The value of technological advance in
decarbonizing the U.S. economy." Energy Economics, 30(6), 2930–2946.
Roy, C.C., Varghsese, O.K., Paolose, M., and Grimes, C.A. (2010). "Toward solar fuels:
photocatalytic conversion of carbon dioxide to hydrocarbons." ACS Nano, 4,
Seyfang, G. (2010). "Community action for sustainable housing: Building a low-carbon
future." Energy Policy, 38(12), 7624‒7633.
Song, C. (2006). “Global challenges and strategies for control, conversion and utilization
of CO2 for sustainable development involving energy, catalysis, adsorption and
chemical processing.” Catalysis Today, 115, 2–32.
Stangland, E.E., Stavens, K.B., Andres, R.P., and Delgass, W.N. (2000).
"Characterization of gold-titania catalysts via oxidation of propylene to
propylene oxide." Journal of Catalysis, 191(2), 332–347.
Sun, D., and Zhai, H. (2007). "Polyoxometalate as co-catalyst of tetrabutylammonium
bromide in polyethylene glycol (PEG) for coupling reaction of CO2 and
propylene oxide or ethylene oxide." Catalysis Communications, 8(7), 1027–
Thambimuthu, K., Davison, J., and Gupta, M. (2002). “CO2 capture and reuse.”
Proceedings of the IPCC Workshop on Carbon Dioxide Capture and Storage.
18–21 November 2002, Regina, Canada.
Tominaga, Y., Shimomura, T., and Nakamura, M. (2010). "Alternating copolymers of
carbon dioxide with glycidyl ethers for novel ion-conductive polymer
electrolytes." Polymer, 51(19), 4295–4298.
Toyir, J., Ramírez de la Piscina, P., Fierro, J.L.G., and Homs, N. (2001). "Highly
effective conversion of CO2 to methanol over supported and promoted copperbased catalysts: influence of support and promoter." Applied Catalysis B:
Environmental, 29, 207–215.
van Alphen, K., Noothout, P.M., Hekkert, M.P., and Turkenburg, W.C. (2010).
"Evaluating the development of carbon capture and storage technologies in the
United States." Renewable and Sustainable Energy Reviews, 14(3), 971–986.
van Schilt, M., Kemmere, M., and Keurentjes, J. (2006). "Process development for the
catalytic conversion of cyclohexene oxide and carbon dioxide into
poly(cyclohexene carbonate)." Catalysis Today, 115(1–4), 162–169.
Wang, J.T., Zhu, Q., Lu, X.L., and Meng, Y.Z. (2005). "ZnGA-MMT catalyzed the
copolymerization of carbon dioxide with propylene oxide." European Polymer
Journal, 41(5), 1108–1114.
CARBON CAPTURE AND STORAGE
Wang, J.-Q., Kong, D.-L., Chen, J.-Y., Cai, F., and He, L.-N. (2006). "Synthesis of
cyclic carbonates from epoxides and carbon dioxide over silica-supported
quaternary ammonium salts under supercritical conditions." Journal of
Molecular Catalysis A: Chemical, 249(1–2), 143–148.
Yasuda, H., He, L.-N., Sakakura, T., and Hu, C. (2005). "Efficient synthesis of cyclic
carbonate from carbon dioxide catalyzed by polyoxometalate: the remarkable
effects of metal substitution." Journal of Catalysis, 233(1), 119–122.
Yeh, S., and Sperling, D. (2010). "Low carbon fuel standards: Implementation scenarios
and challenges." Energy Policy, 38(11), 6955–6965.
Yin, X., Moss, J.R. (1999). ‘‘Recent developments in the activation of carbon dioxide by
metal complexes.’’ Coordinat. Chem. Rev., 181, 27–59.
Zevenhoven, R., Eloneva, S., and Teir, S. (2006). "Chemical fixation of CO2 in
carbonates: Routes to valuable products and long-term storage." Catalysis Today,
Zhang, S., Chen, Y., Li, F., Lu, X., Dai, W., and Mori, R. (2006). "Fixation and
conversion of CO2 using ionic liquids." Catalysis Today, 115(1–4), 61–69.
Zhang, T.C., and Surampalli, R.Y. (2013). “Carbon capture and storage for mitigating
climate changes.” Chapter 20 in Climate Change Modeling, Mitigation and
Adaptation, Surampalli, R., Zhang, T.C., Ojha, C.S.P., Gurjar, B.R., Tyagi, R.D.,
and Kao, C.M. (eds.), ASCE, Reston, Virginia, February 2013.
Carbon Dioxide Capture Technology for
Coal-powered Electricity Industry
C. M. Kao, Z. H. Yang, R. Y. Surampalli, and Tian C. Zhang
Many different sources contribute significant amounts of carbon into the
atmosphere, including combustion, industrial processes, respiration and decay, and
volcanic activities This has caused the buildup of greenhouse gases (GHGs) in the
atmosphere and also resulted in the global climate change. It is well known that carbon
dioxide (CO2) is the main GHG, contributing to the greenhouse warming effect by 81%
(VGB 2004), and fossil-fuel-burning power plants are the single-largest contributor to
CO2 emission. Therefore, innovative technologies for capturing CO2 from these
fossil-fuel-burning power plants and storing it in geologic formations, that is, carbon
capture and storage (CCS), have been developed. CCS is a process consisting of the
separation and capture of CO2 from industrial and energy-related sources, transport to a
storage location and long-term isolation from the atmosphere (IPCC 2005; Plasynski et
al. 2009; Wang et al. 2011; Padurean et al. 2012; Zhang and Surampulli 2012).
Currently, CCS has become one of the major methods to reduce the CO2 emissions to the
atmosphere and mitigate the deterioration of global warming. To establish significant
CCS capabilities, more efforts are necessary to make the CCS technologies more
applicable, practical, efficient, and cost effective.
The focus of this chapter is on CO2 capture technology for the coal-fired power
plants as coal-fired plants emit significantly more CO2 than natural gas plants. This topic
has been addressed and researched/reviewed since the early 1940s (e.g., Tepe and Dodge
1943; Spector and Dodge 1946; Riemer et al. 1993; USDOE 1999; Herzog 2001;
Anderson and Newell 2003; VGB 2004; IPCC 2005; IEA 2009; Lackner and Brennan
2009; CCCSRP 2010; ITF 2010). However, information related to the topic is
overwhelming and difficult to digest. Therefore, this chapter will serve as an
introductory guideline to the topic. Specifically, the chapter will discuss the basic
principles of CO2 capture technologies, the major approaches and alternatives to
CARBON CAPTURE AND STORAGE
capturing CO2, the current issues and future perspectives. The chapter also provides a
list of references for the audiences who need detailed reviews of CO2 capture
technologies and cutting-edge research.
CO2 Capture Technologies
8.2.1 General Means for CO2 Capture
CO2 capture technologies themselves are not new. In the 1940s, chemical
solvents (e.g., monoethanolamine (MEA)-based solvents) were developed to remove
acid gases (e.g., CO2 and H2S) from impure natural gas to boost the heating value of
natural gas. The same or similar solvents were used to recover CO2 from their flue gases
for application in the foods-processing and chemicals industries by power plants. On the
other hand, the feasibility of capturing CO2 from ambient air was evaluated in the 1940s
(Tepe and Dodge 1943; Spector and Dodge 1946). Carbon dioxide removal technology
has been developed and used as a standard process in gas production industry (e.g.,
natural gas, hydrogen gas). Carbon dioxide needs to be removed before the product can
be used and sold. Therefore, many CO2 removal systems have been constructed and
operated in these gas production plants (Plasynski et al. 2009).
Carbon capture technologies can be categorized as a) physical/chemical and
biological technologies (Table 8.1) and b) technologies for carbon capture from
concentrated point sources and mobile/distributed point- or non-point sources (Table
8.2). On-site capture is the most viable approach for large sources and initially offers the
most cost-effective avenue to sequestration. The remainder of this chapter will mainly
cover CO2 capture technologies for the coal-fired power plants, that is, the physical and
chemical (sorption-based) technologies for capturing CO2 from post-, pre- or
oxy-combustion processes from coal-fired plants. Those interested in carbon capture via
biological technologies or from mobile/diluted point- or non-point sources are directed
to elsewhere (e.g., Zhang and Surampalli 2012).
8.2.2 CO2 Capture Technologies for Coal-fired Power Plants
The choice of a suitable technology for CO2 capture depends on power plant
technology as it dictates the characteristics of the flue gas stream. In a fossil-fuel power
station, coal, natural gas or petroleum (oil) can be used to produce electricity. Table 8.3
shows the variety of power plant fuels and technologies that affect the choice of CO2
capture systems. As shown in Table 8.4 (VGB 2004), of the fossil-fuel plants, for a fixed
amount of fuel feed, coal-fired plants emit about twice as much CO2 as natural gas
plants, and thus, will be the focus for us to introduce CO2 capture technology.