SusChemE 2015
International Conference on Sustainable Chemistry & Engineering
October 8-9, 2015, Hotel Lalit, Mumbai
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High Temperature Carbon Capture using of Limestone doped with Flyash
B.Sreenivasulua, I.Sreedhar a,*, K.V.Raghavanb, B.Mahipal Reddyc
a
Department of Chemical Engineering, BITS Pilani Hyderabad Campus, Shameerpet, Hyderabad-78, India
Reaction Engineering Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
c
Inorganic and Physical Chemistry Division, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
Email: vasulu.b@gmail.com,isreedhar@hyderabad.bits-pilani.ac.in,ondapuramiict@gmail.com,bmreddy@iict.res.in
b
-----------------------------------------------------------------------------------------------------------------------------1.
Introduction
High temperature CO2 capture (CC) has gained societal and industrial significance due to global warming.
It is mainly due to the CO2 emissions from thermal power generation stations which are the prime source of energy
for the world. But, industrial flue gas emissions are at ambient conditions. Liquid absorbents, organic adsorbents and
hybrid forms of metal organic frameworks provide high CO2 capture capacity. But, The liquid absorbents suffer
from higher energy penalty and disposal hazards [1]. These also suffer from drawbacks viz., flue gas
contaminations, moisture, fewer life cycles and scale-up issues. Alkaline earth metals are good to capture CO2 but
are expensive with environmental hazards. The only option is to use abundantly available low cost ecofriendly
mineral like limestone [2]. It captures CO2 at temperatures >400oC and its spent material could be used in cement
industry. Lower number of calcination-carbonation cycles is a major drawback due to its pore blocking nature. It is
due to minimal surface area for adsorption in its native form. This could be resolved by the addition of inert
materials like industrial flyash to increase pore size and surface area [3].
For our study, we synthesized limestone with flyash based monolith. Surface area, pore sizes, crushing
strength, CO2 adsorption capacities, SEM analysis and X-RD analysis were measured during carbon capture and
analyzed.
2. Materials and Experimental Methods
The solid adsorbents are synthesized with organic binding agent for pelletizing monoliths. These are again
sintered in a muffle furnace to a temperature of 1050 oC. These are used in the following interpreted experimental
setup. The CO2 capture capacities on doped limestone with CFA based adsorbents at 5%, 10%, 15% were measured
using gas analyzer connected to the set-up.
Fig.1. Schematic of the experimental set-up
3. Results and Discussions
The following Table.1, shows the parameters that were measured. BET surface areas were measured for
different compositions to find porosity with corresponding CO 2 adsorption capacities (1st cycle) with sample weight
of 100g monoliths. Adsorption isotherms were compared with Langmuir and Freundlich isotherms. For different
CO2/N2 gas compositions with SEM analysis were shown in Fig 1, Fig 2 and Fig 3.
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SusChemE 2015
International Conference on Sustainable Chemistry & Engineering
October 8-9, 2015, Hotel Lalit, Mumbai
------------------------------------------------------------------------------------------------------------------------------Table 1 Adsorbent pore size with capture capacity
Composition
Crushing
value Surface
(MPa)
& area (m2/g)
morphology
50%CFA+50%limestone - &Powder
3.42
60%CFA+40%limestone 0.06& monolith
2.83
70%CFA+30%limestone 0.2& monolith
2.18
80%CFA+20%limestone 0.4 & monolith
1.64
Surface
volume(cm3/g)
Pore size
(Ǻ)
CO2 capture
(g CO2/gads)
0.00652
0.00459
0.003
0.0019
76.257
64.87
55.046
46.341
0.192
0.103
0.082
0.04
Fig.1: flue gas CO2 concentration (%CO2) vs time of adsorption.
Fig 2. Fresh sample
Fig 3. Sample after 1st Cycle
4. Conclusions
`
Different combinations of cost effective adsorbents are compared with reference to their performance in
CC, their pore size and volume, physicochemical changes during CC. By comparing CC with time, the intrinsic
adsorption kinetics was done by comparing our results with Langmuir and Freundlich isotherms to identify the
suitable mechanisms.
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SusChemE 2015
International Conference on Sustainable Chemistry & Engineering
October 8-9, 2015, Hotel Lalit, Mumbai
------------------------------------------------------------------------------------------------------------------------------References:
[1]
D.Y.C. Leung, G. Caramanna, M.M. Maroto-Valer, Renew. Sustain. Energy Rev. 39 (2014), 426–443.
[2]
S. Kumar, S.K. Saxena, Mater. Renew. Sustain. Energy. 3 (2014)1-15.
[3]
B. Sreenivasulu, D. V Gayatri, I. Sreedhar, K. V Raghavan, Renew. Sustain. Energy Rev. 41 (2015) 1324–
1350.
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