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Interactions between Char and CO2
- to Create a Cradle-to-Cradle Carbon Cycle, and,- to Develop Advanced Sorbents for Carbon Capture
Wei-Yin ChenNosa O. Egiebor
Daniell L. Mattern
University of Mississippi
See also: AIChE Journal. 60(3), 1054-1065 (2014).
www.see.uwa.edu.au/research/soil-biology 1
Outline Objective in broad sense Early results led to two focused technologies
• biochar pretreatment prior to co-gasification
• carbon capture by functionalized nanocarbons and PAHs from biochar
Synthesis of concepts and hypotheses Experimental results
• Role of sonication
• Roles of thermal and photochemical treatments
• Role of CO2
Technological benefits Development plan Conclusions
www.abc.net.au/science/articles/2009/03/04/2507238.htm 2
Objective in Broad Sense
To explore transformative routes of CO2 fixations on different types of carbons as many
• CO2 capture processes, and
• CO2 utilization processes, including new cradle-to-cradle routes for CO2 reuse,
involve CO2 fixations on carbon as the first step in the process.
3
Two Routes of Special Interests
• Photochemical route
• Need to bring CO2 to high energy levels; i.e., to create a cradle-to-cradle carbon cycle
• Solar energy is renewable
• Demonstrated photochemical CO2 fixation on carbon
• Ultrasonic route
• Demonstrated mineral leaching
• Demonstrated water splitting
• Demonstrated graphite oxide exfoliation4
Initial Results Led to the Current Focuses
• To develop a char-pretreatment process prior to gasification
• to develop advanced sorbents based on functionalized nanographene oxide for CO2 capture
oregonstate.edu/orb/terms?title=b
5
Key Results of Current Study
• Pretreatment of biochar with CO2 and H2O under ultrasound and photochemical treatment prior to gasification• Removal of minerals that cause slagging and fouling in power generation
• Increase in heating value (50%) of biochar
• Increase in hydrogen (9%) content of biochar
• Increase in carbon (13%) content of biochar – CO2 utilization through fixation, and CO2 capture (how was such high level of capture achieved?)
• Exfoliation of graphite oxides in forming single-layer graphene oxide (GO)
• CO2 capture by biochar and functionalized nanographene oxides (NGO) adsorbents• Oxidized polycyclic aromatic hydrocarbons (PAH) and NGO are susceptible to
amine functionalization and then CO2 capture
• Ultrasound can be adopted in producing graphene oxide (GO) from biochar
6
A Recent Emphasis on Gasification Advancement
NETL and EPRI have been developing an efficient gasification technology for low rank coals that uses liquid CO2 as the fuel-carrier for gasification because the liquid CO2, in comparison with water, has
• lower heat of vaporization, • viscosity • surface tension.
The IGCC (integrated gasification combined cycle) plant thermal efficiency improvement on gasifier with liquid-CO2 slurry is about 2.8%.
• Pretreatment of char with CO2 and H2O under ultrasound and/or photo-irradiation provide an even higher synergism for such gasification process since the liquid CO2 and H2O are available in plant.
7
Characteristics of Carbon-Based Adsorbents
• Nanocarbons have large surface area for CO2 capture and functionalization. Procedures for manipulating and functionalizing nanocarbons (such as graphene, CNT, GO and GOF) have been well-established. But CO2 capture on these carbon materials has not been systematically investigated.
• Adsorbents have lower heat capacity than those of liquid solvents – regeneration of adsorbents requires lower sensible heat than liquid solvents.
• Heat of decarboxylation, 24 to 29 kJ per mol of CO2, is comparable to those of amine-based sorbent regeneration processes.
• Amine-functionalization is a highly desirable step in increasing the CO2/H2 selectivity for pre-combustion CO2 capture.
• Nano-grahene oxide platelets can be clamped on SiO2 with strong adhesion force; SiO2 is a strong adsorbent base ideal for harsh capture conditions.
Graphene Oxide (GO)
Graphene/carbon nanotube (CNT) hybrid (CEP, January, 2013)
8
Synthesis of Concepts• CO2 fixation on the edge of aromatic carbons
• Reductive photocatalytic carboxylation of edge carbons of polycyclic aromatic hydrocarbons
• Ultrasound-induced reactions such as mineral removal, water splitting and exfoliation of graphite oxide
• H2O as a hydrogen donor
• Carbon swelling by polar solvents
• Supercritical (SC) CO2 treatment followed by rapid expansion
• Biochar’s unique physical and chemical structure• Functionalization of epoxy, carboxyl and hydrooxyl groups of
graphene oxide with amines
9
Reactivity of Aromatic Carbons – Kolbe-Schmitt Reaction (1860)
The heats of decarboxylation of a few reported carboxylic acids, 24 to 29 kJ per mol of CO2, are well within the range of current sorbent regeneration processes by using amines.
Our Postulation:Carboxylation of edge carbons of PAHs is an effective CO2 capture route.
10
Reactivity of Aromatic Carbons – Reductive Photocarboxylation
Chateauneuf et al. (2002) used supercritical CO2 in their reductive photo-carboxylation experiments, and discover the near complete conversion and the following mechanism:
2
2 2
*
Pr
hPAH PAH DMA PAH CO
PAH CO i OH H PAH CO
where DMA denotes N,N-dimethylaniline (an electron donor) and iPrOH 2-propanol (a hydrogen donor), respectively.
Our Postulations:Reductive photo-carboxylation of edge carbons of PAHs be considered as a mean to enhance the hydrogen
content, thus the energy content, of the reactant,
capture CO2.11
Dihydrocarboxylic acid, I, is the major product only when a hydrogen donor such as 2-
propanol is present (Chateaunef et al., 2002).
Ultrasound-Induced Exfoliation of Graphene and Graphene Oxide (GO)
Chars derived from coals and biomass and petroleum coke have graphitic and GO clusters in their structures.
Our postulations:• Ultrasound exfoliates the graphitic and GO clusters in chars into single-layered
graphene and GO platelets, and therefore facilitate the reactivity of edge carbons of these platelets.
• It is also known that ultrasound splits water; the impacts of the proton and hydroxyl radical after water splitting on the char during treatment cannot be predicted.
• Ultrasound treatment removes minerals as leaching minerals from carbonaceous materials is a known technology.
Pioneering work of ultrasonic conversion of graphite oxide to graphene oxide:Stankovich, et al., Graphene-based composite materials. Nature. 2006, 442, 282-286.
12
Coal Swelling by Polar Solvents
Attacks of nucleophilic solvents breaks the hydrogen bonds, catalyzes the tautomerization, weakens cross covalent linkages in the carbon structure, and swells the coal matrix.
Gasification of type I and type III particles (Wall et al., 2002):
Our Postulations:Treatment of carbons with CO2 and H2O can• swell the carbon,• increase the internal surface area, and,• increase the reactivity of carbon.
www.growingnewlife.com/index.php?p=1_12_Benefits-of-Biochar 13
Fluid Properties at Supercritical (SC) State Fluid under SC condition has both gas and
liquid properties Density increases rapidly near the critical point
(c.p.)
Surface tension decreases dramatically near c.p.
Diffusivity increases dramatically near the c.p.
These properties facilitate fluid penetration, gas/solid reaction and extraction such as the ammonia fiber explosion (AFEX) process of biomass (Dale et al.)
Our Postulation:Rapid expansion from high pressure
treatment of carbon with CO2 and H2O disrupts carbon structure and enhances the reactivity.
14http://www.treepower.org/biochar/main.html
Rationale of Our Study of (Biochar+CO2+H2O)
Our postulations:• Photochemical treatment of biochar with CO2 and H2O leads to reductive
carboxylation (i.e., reductive CO2 fixation) such as that mentioned by Chateauneuf, et al. (2002) (see an earlier slide).
• Treatment by supercritical CO2 is expected to enhance the effects. • Ultrasound exfoliates graphite and graphene oxide clusters, and removes
minerals.
• Biochar contains stacks of graphene and GO layers (Hammes and Schmidt, 2009),
• Biochar contains TiO2, which enhances the photocatalytic reactions,
• Water and/or ethanol could serve as hydrogen donors.
15
Biochar Production and Treatment Conditions
Biochar Production
• sorghum
• 75 and 106 µm
• heated in He with 5 ºC/min heating ramp to 550 ºC followed by a 10 min holding time
Ultrasound and photochemical Treatment
• 3 to 6 gm biochar + H2O + saturated CO2
• 65 ºC, 1 atm
• 3 min, 12 min, 5 h
16
Treatment of Biochar with (CO2+H2O) under Magnetic Stirring
• Notable weight loss during both treatments,
• Loss of mineral matters, Si, Na, K
• Gain of hydrogen during photochemical treatment,
• Increases in both C/O and H/O ratios during photochemical treatment,
• Near 20% increase in heating value,
• 19-fold increase in internal surface area.
17
3 gm biochar + H2O + saturated CO2
1 atm, 5 h Moisturea 6.95 7.2 - 5.66 -
Asha 29.46 19.2 -43.0% 22.56 -33.0%
Fixed Carbona 46.42 57.73 8.1% 55.53 4.1%
Volatilesa 17.28 15.87 -20.1% 16.25 -18.1%
Carbona 55.35 64.85 1.9% 62.4 -1.9%
Hydrogena 1.895 1.84 -16.0% 2.71 24.0%
Nitrogena 0.595 0.62 -9.3% 0.81 18.0%
Oxygena (by difference)
12.62 13.41 -0.1% 11.52 -0.3%
Sulfura 0.08 0.08 -13.0% < 0.05 >-45%
Organicsa 70.54 80.8 -0.1% 77.44 -2.2%Overall Weight Change (dried)
- - -13.0% - -12.0%
Atomic C/O ratio
5.85 6.45 10.3% 7.22 23.5%
Atomic H/O ratio
2.40 2.20 -8.6% 3.76 56.7%
BET Surface Area (m2/g)
12.9 252.2 1855.0% 256.6 1889.1%
Heating Value (kcal/g)
4.83 5.63 16.6% 5.76 19.3%
K, % of total
samplea 5.75 0.914 -91.0% 0.779 -92.0%
Na, wt ppma 603 <445 > -58% <411 > -61%
Si, % of total
samplea8.71 4.65 -70.0% 4.34 -57.0%
ANALYSIS\ SAMPLES
Change during
treatment (wt%)
Change during
treatment (wt%)
Raw Biochar (wt)
Thermally Treated
wt%
Photochemically Treated
(wt%)
Treatment of Biochar with (CO2+H2O) under Ultrasound
• Both treatments result in high
• Weight loss,• Losses of minerals
detrimental to power generation,
• Gain in hydrogen,• Increase in carbon
content, 13%,• Increases in C/O and H/O
ratios,• Increase in heating value,
50%!
• The 11-fold increases in internal surface area are lower than those from stirred treatments w/o ultrasound – due to exfoliation of GO?
• Technological applications – to be discussed later.
18
Moisturea 6.95 2.16 - 2.36 -
Asha 29.46 11.4 -70.2% 11.8 -68.0%
Fixed Carbona 46.42 70 16.1% 70.7 21.8%
Volatilesa 17.28 16.5 -26.4% 15.1 -30.1%
Carbona 55.35 81.2 13.0% 80.1 15.8%
Hydrogena 1.895 2.68 8.9% 2.66 12.3%
Nitrogena 0.595 0.68 -12.0% 0.62 -17.0%
Oxygena (by difference)
12.62 3.98 -1.2% 4.76 -1.1%
Sulfura 0.08 0.06 -42.2% 0.06 -40.0%
Organicsa 70.54 88.6 -1.6% 88.2 0.0%
Overall Weight Change , %
- - -23.0% - -20.0%
Atomic C/O ratio
5.85 27.20 365.2% 22.44 283.7%
Atomic H/O ratio
2.40 10.77 348.4% 8.94 272.2%
BET Surface Area (m2/g)
12.91 151.41 1072.8% 171.74 1230.3%
Heating Value (kcal/g)
4.83 7.26 50.3% 7.18 48.7%
K, % of total
samplea 5.75 0.51 -97.4% 0.55 -97.0%
Na, w ppma 603 456 -77.5% <809 >58.5%
Si, % of total
samplea8.71 3.92 -86.6% 4.27 -76.2%
ANALYSIS\SAMPLES
Change during
treatment (wt%)
Change during
treatment (wt%)
Raw Biochar (wt%)
Thermally Treated (wt%)
Photochemically Treated wt%
Treatment of Biochar with H2O Only (no CO2) under Ultrasound
• Previously observed benefits in heating value, 40%, is between the two previous tests,
• Remarkable photo-hydrogenation, 27.7%, of char by water is achieved,
• Photo-irradiation enhances hydrogenation, and ultrasound enhances carbon fixation.
• Limited increase in surface areas,
• Roles of CO2 are definite.
19
Moisturea 6.95 3.77 - 3.63 -
Asha 29.46 12.4 -65.5% 13.1 -63.5%
Fixed Carbona 46.42 61.4 8.6% 53.6 -5.3%
Volatilesa 17.28 22.4 6.3% 29.7 41.0%
Carbona 55.35
75 11.1% 71.4 5.8%
Hydrogena 1.895 2.54 9.9% 2.95 27.7%
Nitrogena 0.595 0.67 -7.7% 0.76 4.7%
Oxygena (by difference)
12.62 9.39 -0.6% 11.8 -0.4%
Sulfura 0.08 0.05 -48.8% 0.05 -48.8%
Organicsa 70.54 87.6 0.9% 86.9 0.5%
Overall Weight Change
- - -18.0% - -18.0%
Atomic C/O ratio
5.85 10.65 82.1% 8.07 38.0%
Atomic H/O ratio
2.40 4.33 80.1% 4.00 66.5%
BET Surface Area (m2/g)
12.9 45.12 249.8% 76.94 496.4%
Heating Value (kcal/g)
4.83 6.76 40.0% 6.5 34.6%
K, % of total
samplea 5.75 1.01 -93.9% 1.02 -93.9%
Na, w ppma 603 <851 >-54.3% <684 >58.6% Si, % of total
samplea8.71 3.7 >-85.3% 3.45 >-78.1%
ANALYSIS\SAMPLES
Change during
treatment (wt%)
Change during
treatment (wt%)
Raw Biochar (wt%)
Thermally Treated (wt%)
Photochemically Treated wt%
FTIR Spectra of Raw and Treated Biochar with CO2 (under Magnetic Stirring)
Carboxylation (CO2 fixation) is evident.
Reactions between Treated and Raw Biochars – mostly Implied by FTIR Spectra
• Kolbe-Schmitt Reaction (Carboxylation)
• Reductive photocarboxylation, Chateauneuf, et al. (2002)
• Breakage of Ester (Hydrolysis)
• Breakage of Ether
• Radical Ion Formation
• Dissolution of Salts
2RO CO ROCOO
21
2RCOOM H O RCOOH M OH
Effects of Ultrasound Power on Biochar’s Heating Value
• Short ultrasound treatment time, e.g., 3 min, results in a 19% increase in heating value.
• Energy consumed by the sonicator in 3 min is 0.84 kcal/g, which is a major fraction of the increase in heating value of the biochar, 0.91 kcal/g.
• But a major portion of the ultrasonic energy is dissipated into the environment, not by the solution in the flask.
• Ultrasonic energy can be most efficiently used by directly inserting a high powered ultrasonic horn in the solution in the treatment reactor.
22
Treatment of Biochar with (CO2+H2O) under 3 min Ultrasound
• The increase in heating value is caused by both loss of minerals and carbon attachment.
23
Moisturea 6.95 4.07 -
Asha 29.46 24.40 -25.8%
Carbona 55.35 65.44 5.9%
Hydrogena 1.91 1.84 -13.7%
Nitrogena 0.59 0.61 -7.4%
Oxygena (by difference)
12.62 7.62 -45.9%
Sulfura 0.08 0.09 0.8%
Organicsa 70.54 75.6 -4.0%Overall Weight Change (dried)
- - -10.4%
Atomic C/O ratio
5.85 11.45 95.8%
Atomic H/O ratio
2.42 3.86 59.5%
BET Surface Area (m2/g)
12.9 118.9 821.7%
Heating Value (kcal/g)
4.83 5.74 18.8%
K, % of total
samplea 5.75 1.26 -83.74%
Na, wt ppma 603 734 -9.67%Si, % of total
samplea8.71 8.90 -24.17%
ANALYSIS\ SAMPLES
Raw Biochar (wt)
Ultrasound Treated 3-min
(wt%)
Difference (wt%)
Positive Technological Implications
Gasification – energy efficiency, CO2 utilization, less operational problems
CO2 Capture by char and functionalized nanographenes adsorbents
24
A Recent Emphasis on Gasification Advancement
NETL and EPRI have been developing an efficient gasification technology for low rank coals that uses liquid CO2 as the fuel-carrier for gasification because the liquid CO2, in comparison with water, has
• lower heat of vaporization, • viscosity • surface tension.
The IGCC (integrated gasification combined cycle) plant thermal efficiency improvement on gasifier with liquid-CO2 slurry is about 2.8%.
• Pretreatment of char with CO2 and H2O under ultrasound and/or photo-irradiation provide an even higher synergism for such gasification process since the liquid CO2 and H2O are available in plant.
25
Benefits of (Biochar+CO2+H2O) Pretreatment under Sonication to Power Generation
Liquid CO2 at high P is available in power plants, which can be brought to supercritical state easily since the critical temperature of CO2 is only 31.2 ºC.
Residual heat is also available in power plants.
The observed pretreatment benefits are expected to be higher at gasification pressure, e.g., 20 atm; our experiments were conducted at 1 atm.
The pretreatment concept is expected to
• enhance the thermal efficiency (heating value) and power generation rate (more porous nature),
• exhibit less operational issues such as fouling and slagging (removal of detrimental minerals),
• offer a new CO2 utilization route (CO2 used in treatment and gasification),
• offer a waste (biochar) utilization route.
26
The Pretreatment Creates a “Cradle-to-Cradle” Carbon Cycle!
In a co-generation process where 20% of energy input comes from char, treatment results in• 13% gain in carbon and therefore 2.6% carbon recycle - the addition of a pretreatment
unit renders it possible to recycle about 2.6% of burned carbon fixed in the char.• Assuming char’s heating value increases by 50% and 20% of such increase is
used in the pretreatment process, the energy output from combustion of char will be 1.40 times of the original char. For a co-generation power plant that uses only 20% char as fuel source (with the rest of the energy source comes from coal or biomass), the overall energy output from char will increase to 28% (20%×1.40), resulting in a net gain of 8% in the total output. This is not considered an incremental improvement for power plants. 27
Biochar, Functionalized Nanographene or Graphene Oxide (GO) for CO2 Capture
• Biochar’s carbon content increases by 13% during ultrasound treatment suggesting the possible new route for CO2 capture.
• Graphene oxides (GO), clamped on fumed SiO2, will be an effective building block for CO2-capture adsorbents that can sustain the harsh operating conditions.
• Examples are given in the next few slides.
Functionalized GO
(1) oxidation of graphite to graphite oxide, (Park and Ruoff, 2012),(2) exfoliation of graphite oxide by ultrasound, (Park and Ruoff, 2012),(3) functionalization by amine, see next few slides.
28
Functionalized Nanographene or Graphene Oxide (GO) for CO2 Adsorption
Two routes that are considered for grafting tetraethylenepentamine (TEPA) on the two major oxygen functional groups on GO: carboxylic acids and epoxides. The functionalized GO can then be used as CO2-capture adsorbents. Published work also demonstrated that GO sheets can be clamped to silicon oxide substrate by strong van der Waals force (due to its thin nature); thus, amine functionalized GO-SiO2 beads could serve as a strong CO2-capture adsorbent that sustains harsh environments. GO has a C:O ratio between 2.1 and 2.9, implying the abundance of oxygen functional groups. It should be mentioned that other polyethyleneimines (PEI), and hyper-branched amines can serve the same purpose and produce high CO2 capture capacity.
29
O
HOC
O
OH
N-hydroxysuccinimideEDC
O C O4OH
C
O
NH
2
OH
heat
+ H2N
HN
NH
HN
NH2
NHNH
NHNH2
HN NH
NHNH
NH2
OH
C
O
NH
OH
NH2NH2
HN NH2 NH2
NH
OO
NH
OO
N
OO
N
OO
Graphite Oxide vs Graphene Oxide (GO) for CO2 Adsorption
Zhao et al. (Applied Surface Science, 2012, 258, 4301) showed 53.6 CO2 loading per gram of graphite oxide impregnated with EDA under PCO2 = 0.15 atm and 30 ºC. However, in their work,1. The more reactive single sheets GO was
not used,2. no activation agent was used to enhance
the functionalization,3. hydroxyl groups on GO were not
functionalized for CO2 capture.
30
Indeed, our recent data reveal that single-sheet GO without amine functionalization has a CO2 capture capacity, 49.43 g CO2/g GO, comparable to that of impregnated graphite oxide, and functionalized GO with activation agent should show better results.
CO2 Adsorption by Graphene Oxide Framework (GOF)
Burress et al. (2010) showed a) boronic ester and b) GOF formation. Idealized graphene oxide framework (GOF) materials proposed in this study are formed of layers of graphene oxide connected by benzene diboronic acid pillars. The resultant GOF can be oxidized and then grafted with an amine (just like functionalization of GO mentioned in the last slide but with an amine of smaller size, such as ethylenediamine, or EDA) that serves as a potentially potent CO2-chemisorption adsorbent. 31
CO2 Adsorption by Graphene Oxide Framework (GOF) Burress et al. 2010
This GOF (not amine functionalized) showed a ~3 wt% CO2 capture capacity at 310 K when the CO2 pressure is about 0.15 bar (Burress et al. 2010). The capture capacity increases to 12 wt% when the partial pressure increases to 4 bar.
Functionalized GOF is expected to have even higher CO2 capture capacity.32
Other Reactions for CO2 Adsorption by Polycyclic Aromatic Hydrocarbons (PAH)
The versatile roles of NGO and PAH in the development of CO2–capture adsorbents. Chemical, photochemical and photocatalytic reactions of GO and PAH lead to either CO2 capture or a family of functionalized chemicals that can serve as CO2–capture adsorbents.
TiO2-graphene hybrid under UV excitation (Park and Ruoff, 2012).
33
Char as a Possible Source of Graphene Oxide (GO)
Production of single-sheet GO from chars of biomass, coal and petroleum coke. Ultrasound exfoliates graphite clusters (flat sheets in the figure) and graphene oxide clusters (wavy sheets) in chars into single-sheet platelets. Chars derived from relatively low temperatures with a small amount of O2 should produce more GO sheets than graphite sheets, but the optimal processing conditions for different feedstocks are not well studied. The resultant GO platelets will be useful building blocks for functionalization followed by CO2 adsorption.
34
Characteristics of Carbon-Based Adsorbents
• Nanocarbons have large surface area for CO2 capture and functionalization. Procedures for manipulating and functionalizing nanocarbons (such as CNT, GO and GOF) have been well-established. But CO2 capture on theses carbon materials has not been systematically investigated.
• Adsorbents have lower heat capacity than those of liquid solvents – desorption process requires lower sensible heat than liquid solvents.
• Heat of decarboxylation, 24 to 29 kJ per mol of CO2, is comparable to those amine-based sorbent regeneration processes.
• Amine-functionalization is a highly desirable step in increasing the CO2/H2 selectivity for pre-combustion CO2 capture.
• Nano-grahene oxide platelets can be clamped on SiO2 with strong adhesion force, fumed SiO2 is a strong adsorbent base for harsh capture conditions.
novotera.ca/?page_id=10 35
Current Focus on CO2 Capture Sorbent Development in Our Lab
36
graphite has an interlayer spacing of 0.335 nm
exfoliation
graphite oxide has an interlayer spacing about 0.7 nm. It contains contains three major oxygen functional groups: epoxides, phenolics and carboxylic acids
oxidationby modifiedHummers'method
single-layer graphene oxide (GO) platelets. Nano-sized GO contains a rich population of oxygen functional groups that have emerged as the building blocks for many technologies
ultrasonicationH2SO4NaNO3KMnO4
tetraethoxysilane (TEOS)
Production of Adsorbent Base
Production of Graphene Oxide (GO)
sol-gel method
H2O and NaOH
highly porous silica (705 m2/gm) dioxide, SiO2 with basic surface
H2N
HN
NH
HN
NH2
tetraethylenepentamine (TEPA)
functionalization with activation agentsN-hydroxysuccinimide and EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide))
hydroxyl groups on GO are coverted to carboxyl groups
functionalized GO on SiO2
O
C
C
O
OH
OHO
1. orthoester formation2. Claisen thermolysis3. ester hydrolysis
Functionalization
CO2 Capture and Desorption
O C O6
OH
C
O
NH
Cheat
NHNH
NHNH2
HN NH
NHNH
NH2
OH
C
O
NH
C
NH2NH2
HN
NH2 NH2
NH
OO
NH
OO
N
OO
N
OO
NH3
ONH
NH
NH
NH
NH2
O
NH
NH2
NH2
O
O
N
OO
COOH
O
OHOOC
COOH
COOHHOOC
graphene oxide (GO) of nano size clampedon the internal and external surfaces of porous SiO2
Functionalization
Possible Incorporation of the New Concepts in Integrated Gasification Combined Cycle (IGCC)
www.cef-environmental.co.uk/BioChar.htm37
gas and liquid fuels
oxide
graphene
liquid
CO2
CO2
treated char + CO2
H2O for soil amendment
H2O
hot
steam
H2O
air
compressed air
air
oxygen
compressed
H2 CO2
H2
CO2
used adsorbent
char
adsorbed
(batch)
coalbiomasspet. coke
char
gasifier
gas clean up devices
water-shift
CO2
adsorption/ desorption
pyrolysis,partial
oxidation
functionalization
soil amendmentand carbon sequestration in soil
combustor
gas turbine
air separation
unit
air
power generator
heat recovery steam generator
steam turbine power generator
pretreatment
char
compressor
amine
biomass, coal
syngas
syngas cooling& Hg removal
char conversion to
graphene oxide process
ultrasound
sonication or solar Irradiation
hot water
Development Pathways in 3 Years
Pretreatment for Gasification
• effects of P, T, composition, and pH on phase diagram of CO2 / H2O system
• high pressure reactor for sonicated and photo-irradiated treatments
• process parameters: T, P, t, particle size, ultrasound and photo-irradiation power, feedstock (char derived from coal, biomass and petroleum coke),
• pilot-scale tests
• techno-economic analysis
Adsorbent for CO2 Capture
• CO2 Capture by Amine-Functionalized Nanographene Oxides (NGO)
• Photochemical and Ultrasonic Capture of CO2
• CO2 Capture by Phenolic Compounds through Kolbe-Schmidt or Chateauneuf Reactions
• CO2 Capture by Nanographenes derived from Biomass
• Molecular Simulation of Advanced Sorbents for CO2 Capture
• Technological Integration 38
Conclusions• The photocatalytic and
sonochemical reactions of CO2 on the surfaces of carbon are potentially fruitful areas for advanced technologies.
• The two proposed concepts (gasification & CO2 capture) appear promising, but the effects of parameters have to be investigated in the near future.
www.anzbiochar.org/ http://well95490.org/projects/local-food/biochar_grow_soil/ 39
AcknowledgmentsStudents
Mr. Eneruvie OkinedoMr. James Corbett Senter
Mr. Alec MatteiMr. Connor W. Redwine
Ms. Maha YusufMr. W. Richard Meredith
Mr. Will AbbeyMr. Ryan SmithMr. Josh Warren
UM Office of ResearchDr. Alice ClarkMr. Jason Hale
Dr. Walter ChamblissMr. Ken SleeperMs. Allyson Best
CollaboratorsSouthern ResearchSouthern Company
Univ of AkronWorley Parsons Group
Zhejiang UnivNREL
Energy CommercializationWestern Kentucky Univ
National Pingtung Univ of Sci. & Tech.
40
Previous FundingDoENSF
US Small Business Admin.
Comments and questions?
Wei-Yin ChenProfessorChemical EngineeringUniversity of Mississippi(662) [email protected] www.engineering.olemiss.edu/~cmchengs/
www.charcoalremedies.com/charcoaltimes/0512/biochar_revolution
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