Hydrocarbon Processing - June 2021 - 64

Sustainability
CO2 in flue gas from a coal-fired power plant/FCC flue gas and
natural gas-fired power plant, respectively.
Unlike in a conventional amine absorption system-where it
is not possible to minimize energy demand beyond a point since
the heat loss due to evaporation of water is unavoidable-the
proprietary hydrated sorbent process for CO2
capture works on
the principle of circulating fluidized bed reactors with solid hydrated
sorbent circulating between the adsorber and regenerator,
as shown in FIG. 2.
Furthermore, the closer ∆T between adsorption and desorption
allows the heat pump concept to extract and utilize low-temperature
(120°C-180°C) streams available in a refinery or power
plant. This reduces the energy consumption close to 80%-90%
of CAAP, when heat integration is done with a low-temperature
(120°C-180°C) process stream in a refinery and power plant.
A recent circulating fluidized bed pilot plant study with
high-capacity HSC sorbent has demonstrated 93% CO2
removal
on a continuous basis at steady state. The sorbent has
also shown excellent stability. The high-capacity HSC sorbent
has shown 3.2 mmol/g of CO2
capture capacity, which is one
of the highest values among published research, including all
amines and solid sorbents.
The circulating fluidized bed in the HSC process exhibits
a very good heat transfer rate, as in the case of a liquid amine
system. The sorbent is thermally stable, attrition resistant, noncorrosive,
non-sticky/free-flowing in the operating regime and
demonstrates excellent heat transfer and fluidization properties
of Geldart-A particles. The comparison of key parameters for
the proprietary process vs. a conventional amine process for rich
flue gas case is summarized in TABLE 2.
TABLE 2 clearly shows the advantage of the hydrated sorbent
capture over solvent-based commercial techcapture
in
processa for CO2
nologies. The net energy demand for per mol of CO2
the hydrated sorbent process is ~ 40% of the conventional amine
process and less than the hindered amine process. The hydrated
sorbent process creates significant savings in per metric t cost of
a CO2
capture plant by driving down the operating and capital
costs by 70% and 40%, respectively, over the CAAP route.
Takeaway. Solvent-based technologies based on hindered
amine have shown potential progress to develop CO2
capture
technology and reduce CAPEX and OPEX by process heat integration,
use of amine blend solvent and additive, etc. However,
recent developments in hydrated solid sorbent have shown poKey
parameters
Solvent/Sorbent
6
7
tential to substitute a solvent-based technology for CO2
capture.
Unlike gas-liquid contacting for amine-where the absorber vessels'
heights are very large and tall to satisfy the flooding and mass
transfer requirement-the circulating bed system used for CO2
capture is very compact in height and can provide much higher
capacity in a single unit compared to an amine absorption system.
The overall operating cost of the proprietary process is
70% lower, whereas the CAPEX cost is 40% lower than a conventional
amine process (due to the vessel size with no exotic
metallurgy, unlike amine). The hydrated sorbent process is well
demonstrated for continuous sorbent circulating mode in a pilot
plant with 35 kg inventory. The effects of various parameters
were studied and resulted in CO2
power plant, refinery or petrochemicals facility.
ACKNOWLEDGEMENTS
The authors thank Reliance Industries Ltd. (RIL) for its cooperation in executing
all the experiments discussed here.
NOTES
a
Reliance Industries Ltd.'s KM-CDR™ (Kansai Mitsubishi Carbon Dioxide
Recovery) process.
LITERATURE CITED
1 International Energy Agency (EIA), " Global energy and CO2
March 2018.
3
2 Oschatz, M. and M. Antonietti, " A search for selectivity to enable CO2
with porous adsorbents, " Energy & Environmental Science, Iss. 1, 2018.
4 Carbon Capture Journal, Iss. 67, January/February 2019.
5
Chemical Engineering, Vol. 26, Iss. 11, November 2018.
MacDowell, N., N. Florin, A. Buchard, J. Hallett, A. Galindo, G. Jackson, C. S.
Adjiman, C. K. Williams, N. Shah and P. Fennell, " An overview of CO2
technologies, " Energy & Environmental Science, Iss. 11, 2010.
capture
Wang, J., L. Huang, R. Yang, Z. Zhang, J. Wu, Y. Gao, Q. Wang, D. O'Hare and Z.
Zhong, " Recent advances in solid sorbents for CO2
trends, " Energy & Environmental Science, Iss. 11, 2014.
capture and new development
8
Abanades, J. C., B. Arias, A. Lyngfelt, T. Mattisson, D. E. Wiley and H. Li,
" Emerging CO2
Control, 2015.
capture systems, " International Journal of Greenhouse Gas
9
Amte, V., A. K. Das, S. Sengupta, M. Yadav, S. Mandal, A. Pal, A. Gupta, R.
Bhujade, S. R. Akuri and R. Dongara, " Single compression system and process for
capturing carbon dioxide, " Patent #: US10166502B2.
10 Bhattacharyya, D. and D. C. Miller, " Post-combustion CO2
TABLE 2. Performance comparison between the proprietary hydrated sorbent processa
CAAP
MEA
Absorption/Regeneration temp, °C
Reaction enthalpy, kJ/mol
Net energy demand, kJ/mol CO2
Steam (@ 3 bar) required, t/t CO2
Electricity, k Wh/t CO2
Cooling water, ton/ton CO2
Oxidative degradation (mg/Nm3
OPEX, $/t-CO2
)
64 JUNE 2021 | HydrocarbonProcessing.com
35-40/110
72
198
2.1
70
70-105
100
Base
with other capture technologies
Hindered amine process
Sterically hindered amne + promoter
35-45/110
58
97-141
0.98-1.48
110
160-175
0.2-1.5
-
Proprietary HSC processa
solid support
K2CO3
70-90/120-130
60
87
0-0.7
85
40-55
stable
0.3 of base
capture technolostatus
report 2018, "
capture
Haszeldine, R. S., " Carbon capture and storage: How green can black be? " Science,
September 2009.
Nie, L., Y. Mu, J. Jin, J. Chen and J. Mi, " Recent developments and consideration
issues in solid adsorbents for CO2
capture from flue gas, " Chinese Journal of
removal efficiency of > 90%
and purity above 99%. The pilot trial provided definite indications
towards the efficacy and scalability of the hydrated sorbent
process for capturing CO2
from stationary point sources in a
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